Terminator Salvation (2009)
The Cameo: We witness the arrival of the original T-800. Aptly for a cyborg, Schwarzenegger's youthful face was digitally inserted.
If The Character Had More Screen Time: The franchise could really go full circle by following Arnie back to 1984 and the start of The Terminator .
Wayne's World (1992)
The Cameo: Wayne (Mike Myers) is pulled over by a traffic cop, only to realise it's the T-1000 (Robert Patrick) from Terminator 2: Judgement Day .
If The Character Had More Screen Time: It'd be because Skynet had just found out that it's not John Connor who saves the future Earth, it's Garth (Dana Carvey).
24 Hour Party People (2002)
The Cameo: When unreliable narrator Tony Wilson (Steve Coogan) catches Magazine singer Howard Devoto (Martin Hancock) shagging his wife, the real-life Devoto turns up to declare that "I definitely don't remember this happening."
If The Character Had More Screen Time: Hmm… Joy Division? Sure. Happy Mondays? Absolutely. But Magazine? Hardly the stuff of indie music legend.
The Cameo: The best of Quentin Tarantino's many cameos is a suitably wordy (and completely tangential) affair, as he tells a filthy joke before getting gunned down in a shootout.
If The Character Had More Screen Time: The, shall we say, limitations of QT's acting ability would become even more apparent.
Fantastic Mr Fox (2009)
The Cameo: Jarvis Cocker already had a Harry Potter cameo under his belt, but went one better by being turned into stop-motion as banjo-twanging farmer Petey.
If The Character Had More Screen Time: He'd eventually start chronicling the sex lives of Mr and Mrs Fox and all of their animal friends.
Indiana Jones And The Temple Of Doom (1984)
The Cameo: The airport scene at the end of the film's Shanghai sequence is a proper jolly boys' outing, featuring Steven Spielberg and George Lucas as extras, plus Dan Aykroyd as the guy who books Indy onto the worst possible flight out of town.
If The Character Had More Screen Time: To be honest, we're still surprised Aykroyd doesn't rock up in India later in the film.
High Fidelity (2000)
The Cameo: A film about one-upmanship in music taste stands and falls on the quality of its references, and the biggest coup is having The Boss himself, Bruce Springsteen, turn up as mentor to John Cusack's Rob Gordon.
If The Character Had More Screen Time: He'd suffer a backlash at the hands of Rob's snobby record store employee Barry (Jack Black).
The League Of Gentlemen's Apocalypse (2005)
The Cameo: Famously, the fourth member of the League, Jeremy Dyson, never appears on screen. So in a wry in-joke, they kill off 'Dyson' (played by Michael Sheen) before the opening credits.
If The Character Had More Screen Time: The film is already way too meta. Any more actor/character confusion and our heads would probably explode.
Once Upon A Time In The West (1968)
The Cameos: The looong opening sees the great Western character actors Woody Strode and Jack Elam (plus Leone regular Al Mulock) play three gunslingers waiting for - and then gunned down by - Charles Bronson's drifter. But it might have been even better - Leone originally intended for it to be Eastwood, Wallach and Van Cleef.
If The Characters Had More Screen Time: That opening sequence would be even loooonger.
Spider-man 3 (2007)
The Cameo: Sam Raimi cast his old Evil Dead mucker Bruce Campbell in all three Spider-man movies as, respectively, a ring announcer, a snooty usher, and the piece de resistance, this preening, pretentious maitre d'.
If The Character Had More Screen Time: Maybe it's the same character - a secret superhero quietly stalking Peter Parker across the films.