One Steve Limit/Film

Inversions of, and exceptions to, a One Steve Limit in Film include:

Averted in Boys which featured an inordinate number of characters (male lead included) called John.
Captain America: The First Avenger: Zigzagged. It features a seven man elite Army squad that included three-and-a-half characters named James. The half is a guy called Jacques, which is the French form of James. However, only one is ever referred to as James, and he usually goes by his nickname anyway. The others don't ever have their names mentioned, except in the credits.
- Played straight that there is only one Steve.
Alfred Hitchcock's classic Shadow of a Doubt stars Joseph Cotten as an Affably Evil Serial Killer named Charlie, and Teresa Wright as his adoring niece, also named Charlie.
Heathers: three of the lead cast are called Heather. As the name implies.
Die Hard has a duo of FBI Agent Johnsons. No relation. One even answers a phone, "This is Agent Johnson. No, the other one." Die Hard 4.0 has a callback with another Agent Johnson, and McClane reacts with alarm at the name.
In The Science of Sleep there is Stéphane and Stéphanie.
The Big Lebowski: the basis of the entire plot is that a slacker named Jeffrey Lebowski is mistaken for a millionaire of the same name. Nicknamed "The Dude" and "The Big Lebowski" respectively, to avoid confusion.
Pirates of the Caribbean had William Turner (Bootstrap Bill) and his son William Turner (Will). (And HIS son, William Turner the 3rd) Justified Trope since it a common real life naming convention for fathers and sons. It's also used for a throwaway joke.
The sequel to Chinatown, The Two Jakes, says right in the title that there are two primary characters named Jake.
Office Space has 'the Bobs'. And the Lumburghs.
Indiana Jones and the Last Crusade features a father and son pair of Dr. Henry Joneses, which is highlighted when a character greets, "Doctor Jones" and both reply. The younger Jones, however, prefers going by "Indiana" rather than his first name or "Junior." In the fourth film, there's a third Henry Jones.
Night of the Blood Beast may or may not have featured a team of scientists named "Steve", perhaps foreshadowing the IRL Project Steve.
The main character of Groundhog Day is named Phil and of course there's the groundhog, Punxsutawney Phil. Phil, with the typical Bill Murray Typecasting, loathes the rodent even more because of this fact.
My Big Fat Greek Wedding has a funny scene in which the father introduces the extended family. Just about everyone's name is a variation of Anita or Nick.

Gus: Welcome to my home. Over here is my brother, Ted, and his wife, Melissa, and their children, Anita, Diane and Nick. Over here, my brother Tommy, his wife Anzie, and their children, Anita, Diane and Nick. And here, my brother George, his wife Freda, and their children, Anita, Diane and Nick. Taki, Sophie, Kari, Nick, Nick, Nick, Nick, Nick, Nick, Nick, uh, Nikki, and I am Gus.

In Horton Hears a Who!, Morton mentions that Vlad is after Horton. Horton inquires as to whether he means Vlad the Vulture, or Vlad the bunny who gives out cookies.
In Goodfellas, Karen's narration at her wedding reception mentions the abundance of Peters, Pauls and Maries among the guests.
The movie Pirates of Silicon Valley, about the early days of Microsoft and Apple, had three characters who were really named Steve - Jobs, Wozniak, and Ballmer. Risk of confusion was removed by using Ballmer's last name and Wozniak's nickname of 'Woz'.
The animated Ralph Bakshi version of The Lord of the Rings felt that the names Sauron and Saruman were too similar, and so Saruman was renamed to "Aruman". Although they still called him Saruman half the time.
- this DM of the Rings strip spins a joke from the similarity.
Played with in the baseball movie Major League: Back to the Minors. Finding that he has two Juan's on his team, the manager denotes them Juan1 and Juan2. A pitcher with a psychology degree comments about it possibly giving them issues. The manager asks if he'd like to be Juan3.
Black Doug and White Doug in The Hangover.
The Rocky series has two "Duke"s: a good Duke who was Apollo Creed's trainer until Apollo died and then became Rocky's trainer, and an evil Duke who is Tommy Gunn's manager and just wants to make money out of him. Both Dukes are black.
- Also, Rocky's son is Rocky Jr.
The police station in Hot Fuzz has two Andys working there.
In The Terminator, the Terminator kills two other women named Sarah Connor before targeting the future mother of John Connor.
- Also in The Terminator, it's easy to miss but both Traxler and Vukovich (the two police detectives) have the first name Ed.
In Kingdom of Heaven, the producers purposefully changed the name of the historical Raymond of Tripolis to Tiberias because they were afraid the audience would mistake him for Reynald de Chatillon.
In Blazing Saddles, the entire town of Rock Ridge is named "Johnson". Best not to dwell on it...
XXX has "The Ivans."
The Infernal Affairs trilogy has two women called Mary both of whom are successive love objects for Ming.
The Ju-On franchise has two characters called Kyoko. The first one, who has psychic powers and thus can sense that something is very, very wrong with the house, appears in the first two movies, and the second one is (arguably) the protagonist of the fourth movie.
Casino Royale 1967 has Sir James Bond pulled out of retirement, his name and number already given to the one we all know - spearheading a campaign against SMERSH, he gives all his agents (men and women alike) the name James Bond, to keep the enemy confused.
Averted in The Golden Compass where Word of God changed Iofur's (pronounced like Yo-Fur) name to the much more evil sounding Ragnar because it sounded too close to Iorek (said as Yor-ek).
Averted subtly in Unforgiven where the protagonist is called William and the antagonist is called Bill (which is, of course, the short form of William).
Subverted in Letters to Juliet when two Patricias get confused as she thinks there is only one.
The Hammer Horror films suffer from having a lot of characters share names. The Frankenstein movies have a seemingly endless line of guys named Hans, while the Dracula movies seem to have an infestation of Pauls.
Out On A Limb, starring Matthew Broderick, has a pair of brothers both named Jim. "We were named after different people though. I'm named after our Dad, and he was named after our Grandpa."
Played VERY straight in the 2006 film Inside Man starring Denzel Washington and Clive Owen. The main plot of the movie involves a bank heist, led by Owen's character. To confuse the police, victims and any potential witnesses, the members of the heist crew call each other differing variants of "Steve": Stevie, Steve-Oh, etc. The rather amazing thing is how smoothly they work despite this.
American Beauty:

Lester: "That's our neighbour, Jim, and his partner... Jim."

Sister Bridget cruelly enforces this in The Magdalene Sisters. When Rose introduces herself she says they already have a Rose and has everyone call her by her middle name Patricia. Crispina's real name is Harriett so we could assume there was another Harriett in the laundry as well.
Averted in Slumdog Millionaire where Jamal searches the name Latika in the phone listings and gets over 3000 results. Even when he searches Salim K Malik he gets six results.
Averted in Black Swan. The director's name is Thomas. One minor character- one of Lily's friends at the nightclub- is named Tom.
Averted in, of all things, Plan 9 from Outer Space. Jeff's co-pilot is named Danny, and Tor Johnson's character is Inspector Daniel Clay. This is probably just another case of Ed Wood's general problems with internal continuity.
Averted in Gerry with the characters Gerry and Gerry. One of the few examples where this doesn't get confusing because they're the only two characters.
Averted in Mystery Men, with the leaders of the Disco Boys being Tony P and Tony C.
Averted in The Public Enemy. There are two guys named Patrick, but most of the time they're called Paddy Ryan and Pat Burke, so there's no reason to get confused.