There are several Linux based Portable Tablet Computers running on
Android available now and all are instant on. The foremost is the
Motorola Xoom. It got the best of show award in January
ces.cnet.com/motorola-xoom-wins-best-of-show. I'm just about to
purchase one and I'll probably post my impressions in a few days.

Specs: 10.1 capacitive touch screen; stereo speakers; front (2 MP) and
rear (5 MP) camers; 32 GB built in flash memory; 1 GB RAM; 1 GHz dual
core CPU; access to the full Android Marketplace and apparently even
the phone size apps work well and don't look too bad; a hundred or so
Tablet specific apps and growing rapidly. I'm getting the WiFi only
version and will tether to my Dell Streak when necessary, but I don't
anticipate using it "on the run" much.