I think that I’m correct when I say that the Asus Eee PC T91MT is the smallest and cheapest multi-touch enabled computer.
I haven’t got the chance to check it (Probably I will very soon) but to pay about $100-$200 more than equivalent netbook and be able to play with multi-touch and demonstrate the Windows 7 touch capabilities, this is a good deal. The drawbacks: it’s pity that the hard disk is small (32 GB) and also they could have better screen resolution (1024 X 600) and also a better CPU. In a second thought small screen resolution can give better experience with the multi-touch interface because the graphics accelerator and the CPU need to do less work when they need to draw the result image. $532 for a netbook is quiet expensive! $532 for a Windows 7 multi-touch machine is very cheap!