Mary Jo Foley is speculating that we’ll be hearing about a PlayTable implementation with multi-touch gesture support in the near future. That would be cool.
One point to keep in mind is that multi-touch gestures can span a whole range of devices–from UMPCs to projection-based smartboards, to new product categories, such as the PlayTable. Hopefully Microsoft is keeping this in mind as they work through their SDKs. Of course, the hardware (and drivers) is going to be key here. I’m not sure, for instance, if the existing digitizers in UMPCs can be tweaked to support dual or multi-touch gestures.