I SO want to run Usine Pro on an Intel Surface.
http://www.sensomusic.com/usine/
OR even Gesturespark
http://gesturespark.com/

It's the screens that interest me more than the actual performance of the hardware. Being able to build custom interfaces for the touch screen and sending that data over network MIDI to a "real" powerful PC is so much fun but now that you mention it I can see third parties building specialized covers for controlling music software. A 25 key synth sized keyboard with pads, buttons and sliders on top would be great. They could have LED strips embedded in them like the touch strips on the Tempest drum machine or the new Akai Pro MAX 49 controller.

But, like I always say, Windows developers don't seem to care much about audio and rarely have a clue as to what MIDI is.

, Ian2 wrote

Assuming latency isn't a problem (I don't think it will be on the pro in any event) I hope some third party comes up with a music oriented cover (ie piano style keyboard and lots of function keys  / pads for mapping to midi.  That could also be interesting.