I think it's not that big for today's SD's. There are just a bunch of classic-like games (E.g. Earth Worm Jim 2, Mickey Mania, Castlevania SOTN and Lomax) that 32gb or even 16gb at some point can handle it if one is selective. Or do you wanna just keep the whole collection on the concurrent (if this word works here) running SD instead?
But don't get me wrong, cool project!
Edit:
After watching the vid, I don't think it's fast enough to have a good experience with PS games. Long loading times have proven themselves annoying thru time.