Did you see thedaily's take [1] on kinect for laptops? The reason you won't see kinect on a tablet anytime soon is this one observation:

"It murders batteries

Devices in the field must be plugged in whenever possible since the Kinect technology drains juice in a hurry..."

Laptops generally have much larger battery capacity (for example my current laptop has 94Wh while an iPad2 has 25Wh), and if Kinect kills laptop battery, forget about mobile for now.

[1] http://www.thedaily.com/page/2012/01/31/013112-tech-kinect-l...