Only problem will be that Microsoft has in it's contracts with game developers that titles that are relased on multiple platforms can't have any "functionality that gives the competing console a direct advantage over the Xbox 360." So legally, I don't know if Rockstar would be able to provide Vita functionality. What they could do is develop a version of GTAV for the Vita which could work via CrossPlay with the PS3 version, like how Marvel vs. Capcom works, as a way around the contractual obligation to make the 360 version the same or better.
i dont think thats true
A: thats boarderline monopolizing an industry by dening free market competition
and B: if that where true then why do some games such as mortal kombat get content the xbox version did not, giving the ps3 owners a clear advantage. I have both a xbox and ps3 and only bought the ps3 version over the xbox one for that reason. Im not putting past MS to pull that in a contract but i dont think its true anymore if it ever once was