I still love my TR2A, even though I can't write on the screen.
Also consider the Samsung NEXiO S160 reviewed here: http://www.pdabuyersguide.com/nexio_S160.htm. It's not cheap, but it is significantly cheaper than the TR2A. It's an amazing device!
The general idea with XP Tablets is that they should be verging on ultralight classification. The Acer Tablet is about the same size as the TR2A, though it doesn't have an internal optical drive. We have a review of this unit, and there is now a somewhat faster version available. The Compaq XP Tablet is also in the B5-ish family, and is sometimes seen for less than $2,000. Both are convertible designs, which means they have swiveling displays and a standard integrated notebook keyboard.
-------------------- Lisa Gade Editor in Chief, MobileTechReview