canofhumdingers said:

i always thought it would be neat to have Z-95 Headhunters (the precursor to the x-wing in "in-universe" history) in Revenge of the sith.

They're brought up in a conversation Anakin and his friend have with some pilot in Mos Espa in the opening chapters of The Phantom Menace novelization. I still remember reading that a week or so before the movie opened, and by that point I'd pretty much figured out that these chapters wouldn't be in the actual movie so I thought "hmm, well that's a nice nod to the EU."

SilverWook said:

I don't know if it's canon or not, but I recall reading somewhere the Rebels stripped down the Y-wings to make them easier to maintain and so forth.

There should have been "new" versions of many future Rebel workhorses in the prequels. *sigh*

Well, yea, but you're preaching to the choir here. There are plenty of things that are showing up in these various prequel spinoffs that should've been in the movies themselves, simply because the cashcow is still there.