Apart from actor cameos, Tarantino's bound to include subtle homages and head-nods to classic science fiction films as well. Tarantino doesn't just genre bend, but plays around with iconic, tried-and-true aspects of the film's he's drawing inspiration from. Kill Bill is the perfect example, as it's filled to the brim with sequences and camera techniques used in martial arts films. Django Unchained does the same thing with spaghetti westerns, as it introduces memorable aspects of classic films, but reworks them for its own purposes (see: the scene where Dr. King Schultz kills a local sheriff in the street, a nod to "high noon" Western standoffs). Science fiction is a gigantic, varied genre, so the possibilities for homages and head-nods are endless. If Tarantino does in fact pay tribute to Invasion of the Body Snatchers, he could easily homage classic alien-invasion films. Plan 9 From Outer Space comes to mind...