As a proof of concept, this is incredible and definitely where I see RPGs moving (at least as an option, sort of like DDI 2015 or something).
In fact, if:
1) the dice rolling could be done with real dice (use dice with clear enough numbers and it can read the bottom number to determining the top number), and
2) you could use either minis or images (a la Pozas' awesome counters),
then forget proof-of-concept, I would pay to use that tomorrow!!
Of course, it's already easy to envision so many more features that could easily be added. Right off the top of my head, I can imagine a *relatively* straightforward:
-- integrated note-taking system - tag locations with notes, players keep notes by typing on the surface and storing them miniaturized along the edge, etc. - all searchable and able to be keyword tagged for quick reference
-- loot management - that magic sword is an actual icon that can be dragged from the treasure to the PC and even dragged from PC to PC
-- heck, have all campaign resources can be built in so that you can view the setting as a virtual zoomable world (Google Faerun), as an interactive timeline (scroll through history and see text, images, and even video of historical events), NPC listings shown visually to help remember Tom the Barkeep from Thomas the Terrible...
Maybe not as easy, but still feasible - if you use icons rather than miniatures, you could handle 3-dimensional combat easier. Picture an isometric multi-level map with the "current" level visible and the others semi-transparent, so you can see how the different levels relate to each other. Just drag a slider to move the view up and down.
Combat management is just a portion of how RPGs can be integrated into this sort of device. Publishers can release data packs that update the campaign information, so on and so on.
I've thought about this a lot over the past several years. I have even started designs for these sorts of things, but for current market Flash/web tech rather than multitouch surface computing. When I've tried explaining it in the past, people have just scratched their heads confused. Hopefully this sort of thing can show people what the possibilities really are.