Rob, I'd suggest that making an 80s pastiche would be redundant, since many 80s movies fill that role themselves--the Back to the Future films, for example, highlight Marty McFly's quintessential 80sness by plopping him in other time periods. (For example: the scene in which he convinces his own father that he's an alien with the help of a Walkman.) Or Purple Rain, Prince's retelling of his own early career as a hero's journey, but set in the then-present day, not in the seventies when he was actually getting started. Or Tron and The Last Starfighter, saving the world and/or the galaxy with videogames.
To me, the one single movie scene that most exemplifies the eighties is the one in The Terminator in which the T-800 sweeps past Sarah Connor in Tech Noir as the clubgoers dance in slow motion to this song, which sounds itself like Generic 80s Pop--it's even by a band called, dig if U will, Tryanglz--and Kyle Reese waits in the background; even though the cyborg is technically emotionless, it's easy to read an implied cold contempt of the scene and the world in general as not really mattering. The 80s seemed to observe itself like that, as something less than organic, whether it was the inherent weirdness of Marty McFly in any era that he went to, or Prince playing himself as a product of a specific urban subculture that he himself largely created, or imagining worlds in which videogames actually mattered.
I dunno. It's a theory, I guess.