Wipeout Vita has that feature. It's confusing since the Vita version is a brand new game and the multiplayer is against Wipeout Fury players.
So far that, Modnation Racers sharing tracks/characters/karts with the PS3, and Ruin sharing saves have been the cross-platform features.
Gravity Daze is made by Team Siren, btw. It was originally a PS3 game. I'm trying to think of any other relevant news.
I also don't see Vita affecting the PS3 if it had video out, and if anything, if they advertise that feature it could sell more Vita hardware. I don't know how much they make/lose on the PS3, but I would they want to sell more Vita hardware at this point.