To Uwe :
look at this clip it might help you for disassemble :
http://vimeo.com/3933798
the most important is to know that the bezel is glued to the LCD with a double sided sticky strip so be gentle due to disassemble. The other problem are side clips - be careful with them, don't rush, take your time and use some hard plastic plate to unlock them. Dont use knife cause you can scratch the bezel. Sorry that I don't film the process but hope that the clip above will help you.
jingorm - it works for me because I had 7767 BFG model which came with a XGA Multitouch screen. Basically the existing touchscreen is connected to the digitizer PCB . There are 2 types of digitizers for x61 tablet - one is with connector for touch and the other not, so you need the first one. In my case I've bought a naked SXGA+ LCD and moved the existing digitizer and touch on it.
The touch glass is glued to the LCD metal frame with a double sided sticky tape strips (about 5mm wide) across its 4 edges so in order to unglue it you have to use very thin metal blade to cut the sticky tape between lcd and touch ( i've used a blade from a used gillette shaver razor for a single use I don't know the exact name in english ). After taking off the touch glass clean it well from any dust ,stains and remaining glue , apply new double sided sticky tape and glue it on a new screen in exactly same position. Take care to work in a dust free room with rubber gloves in order to prevent any soil to stick between the lcd and touch glass.
The whole time for that mod was about 2 hours ,mostly for the un-glue because I was very careful not to broke the thin touch glass.
I really don't know from where you can buy the parts for this mod if you don't have an XGA multitouch screen for donor.
Keep in mind that basically it is a pain to use a touchscreen on a SXGA resolution because of a small icons but in some software with bigger icons it is usable.