Processing every cut in blade mode would be a nightmare for the Vita, of course it is actually possible but they'd have to significantly reduce the quality, for example making cut parts disappear at a faster rate, lowering texture quality, probably losing consistent 60fps. Besides, it would probably play like ass on the Vita, the sticks are like half the size so half as much movement has to provide the same level of in-game movement you'd get from a pad, which would be horrible for full-manual cameras (or near full, as this game has ****-loads of camera correction), Rising's camera isn't that good as it is let alone on a smaller screen with sticks that have nearly double the sensitivity.
What probably happened is when P* updated the trophy list with Sam's DLC trophies someone there or at Konami or Sony must have accidentally checked a box that updated it as a PS3 & Vita list instead of just a PS3 list. Maybe there's a Vita port intended for release at some point, but it seems unlikely based on what's been said so far (not to mention Konami and KojiPro don't have much in store for the Vita, after MGS HD they seem to have silently cancelled ZOE HD for Vita, and Vita still isn't doing that well so far), don't hold your breath anyway.
As it has been said many times. Rising will never port to the vita because it wouldn't be able to handle it. *sigh*
do you really believe that nonsense? all they have to do is worsen the graphics a litlte bit
But still, to render every single piece in real-time... And not pre-made pieces, randomly cut pieces! The game lags hard when I cut get triple Zandatsu and have like 200 piece-count on the PS3, what makes you think the VITA can handle it? Plus, it's been announced by P* that a Vita version is impossible. It's probably a mistake that PSN hasn't bothered to fix lol. I would LOVE a Vita version though, that'll justify me buying a Vita.