I've been thinking for a while about a project for an old all-in-one pc and decided that I'd like to re-purpose it as a portable Raspberry Pi Pad.
I've stripped the screen from it and intend to attach a touch screen overlay running form one of the USB ports.
I can re-wire the screen to run directly from the HDMI port.
I can build the power supply to run off batteries, I reckon a cheap 12v NiMh, available from any model shop will suffice to start with.
Powering the RasPi on it's own the batteries would be good for approx 30 hours, so once the screen and backlight are taken into account I'd be happy with anything over a couple of hours, although I suspect I can get it into the realms of any current laptop (7/8 hours).
I just need the RasPi to fill the final piece in the jigsaw.
Total project start to finish? approx 4 hours.