According to an interview with Netherrealm Studios executive producer Shaun Himmerick conducted by Industry Gamers, not only does the PSP2 exist, but it's already in developers' hands. When asked about the possibility of the Mortal Kombat reboot heading to PSP or 3DS, Himmerick replied, "We're not launching day one on all consoles like that. We are looking at them; we have a PSP2 in the house and we're looking at the engine, like what can it support."
Wait -- the PSP2, you say? "PSP2 looks like it's a pretty powerful machine," Himmerick added, before saying that his studio doesn't have a 3DS just yet. Sony, as you might imagine, refused to comment.