I don't speak or read Japanese but I just saw this thread on ps3trophies.com that MH4 might be coming to the Vita according to this picture.
As I said, my Japanese is hidden in my brain so here's what has been translated.
The reason for the delay of the 3DS game Monster Hunter 4 isn’t to spend more time to improve the game’s quality: it appears that they’re considering a simultaneous release on PS Vita. Now, Sony is added to the mix in addition to Nintendo to discussing this point with Capcom.
Whilst originally it was said that the delay of MH4 was due to wanting to make a better quality game and graphics, the real reason appears to be that it may be released on the PS Vita to increase sales.
Now I never played a Monster Hunter game but I hear across the internet that this can boost sales for the Vita so I'm hoping it happens. I'd like more developers to make some games for my beautiful Vita.I'd also like to try it out so let us Vita owners cross our fingers. Huh? HUH???