I'm hoping it'll be a download code. Giving away a cart with each blu-ray would get expensive, and would cause non-Vita owners to just sell their cart back to EB Games.
Actually, what I think would be most likely, since Sony seems to love same day digital releases, is if you buy the game on PSN you get both versions for free, like Soundshapes. That'd stop people giving away their download codes. Unless said mentioned the retail Blu-ray..??
I'd also like a portable inFamous, I really want to have a big, open world, console style game on the Vita. Hopefully Assassin's Creed will fill that role for me till we get a portable inFamous.