One controller per console tells me that it's not bluetooth but some kind of ad-hoc wifi n mode.
Bluetooth isn't trustworthy enough for video streaming, i think.
If it really has P7 and R7xxx Cpu and Gpu, it would not have a problem feeding 5 or 6 of these tiny vga-resolution screens. So the limitation is either the lack of ram (or hdd?) or the connection between the U and the peripheral.
And no multi-touch is ok, if you think about it. You're not gonna use the screen for rotating the mini-map but rather push buttons, point to answers and places on maps and sliding from a to b. Gameplay essential stuff.
Sony is closing on Nintendo real hard with the Vita-Ps3 relation.