As someone whose close friend just won Best Animated Short in the Student Academy Awards (run by the same people... check it out, the animation is called Art's Desire), lemme clear up some misconceptions about the Oscar process.
First of all, any film can be considered, as long as it has been screened in Los Angeles. Many film festivals around the country book theater time in Los Angeles for the winners of their festivals, so they get to be officially eligible. THis rule is so members of the academy, most of whom are in Los Angeles, can have a chance to see it.
There ARE other rules, however, like I believe one would have to get the film printed onto 16mm or above film in order for it to be officially screened for Academy members. When my friend was considering submitting her film for the real deal she would have had to shell out a grand or so to get her 4 minute long film shown on film. I can imagine this being cost prohibitive for many flash artists who use flash specifically because it's so cheap.
THAT BEING SAID, let it be remembered that DON HERTZFELDT'S REJECTED was nominated for an Academy Award! So anyone can do it!