The only buttons on the 2730p that are available in slate mode are screen rotate, esc, and the jog dial. I don't think any of them are reprogrammable. There's also an i button the side that I had forgotten about, but it only brings up the HP info center. I bet you could reprogram that one, but there's no quick and easy central interface for it like there is with Motion's dashboard thingy. Then again, I'm running a clean install of Windows 7 on mine and may be missing HP utilities that I didn't get around to installing.
Which reminds me, after using only Windows 7 on tablets, I'm now trying to use XP on the le1600 and it's awful. Stick with Windows 7. It's not just the better handwriting, it's just all around better. I'll try to get some screen comparison shots now, but the more you talk about what you want, the more I think the 2730p may not be the best for your needs. I think the Asus EP121 would have been a great choice except for the battery life. It's got a great screen, Wacom digitizer, core i5, 4GB RAM, but reports are coming in at barely 3 hours of battery.