jkmobile added a touch screen to his Eee PC and he’s posted a video showing how to do it. He was able to find a properly sized after-market touch panel that could be fitted on top of the stock screen just behind the bezel. It then connects to the PC using a USB connection, which he was able to completely hide by soldering the connector directly to the motherboard’s USB pins.
I wasn’t aware that these touch panels were readily available. It looks like this mod could be easily adapted to just about any laptop model. Cool stuff.