I own a ThinkPad X61 Tablet. I am currently looking for a replacement laptop model with a comparably good tablet.
I have most recently reinstalled this machine with Ubuntu Saucy. At the moment, there is a regression in Unity which results in greatly impaired graphics performance; if you use a proper window manager like XMonad there is no problem. Suspend and hibernate still work out of the box. I also can hibernate with an encrypted swap partition on main disk.
I have a home-cooked setup of scripts (partially stolen from Luke) for screen
rotation with the accelerometer. The modified
module that you need can be setup with
m-a a-i tp-smapi. The last
time I checked, the calibration interface did not work, so I have hard-coded
an appropriate calibration parameter.
ThinkWiki had a very excellent set of pages about ThinkPads, though I have not referred to them in a while.