Dave the Lifekludger was loaned a Tablet PC, and has set about experimenting with using it with a mouthstick.  One of the complaints Dave has is that the tablet pen attached to the mouthstick is a bit heavy, much more noticable than the PDA stylus he has attached.  Dave definitely needs one of the pens that comes with my Acer, the one that slides into the silo on the screen.  Its about the same size as a typical PDA stylus.  I couldn't find a picture, but Acer still sells is for about $15.  Of course Acer's accessory site sucks (just choose TravelMAte C110 series and the select the TM100 - STYLUS SLIM PEN-111.)

Good luck with your Tablet PC, Dave.