It's quite easy to build a low cost whiteboard for Linux, using a Wiimote as pointer detector: Low-Cost Multi-point Interactive Whiteboards Using the Wiimote

Linux links:

• Linux electronic Whiteboard (HOWTO)
• Linux electronic whiteboard (Google Code, C implementation)
• [Wiimote Whiteboard (Python implementation) http://wiiwhiteboard.wiki.sourceforge.net/

Hardware HOWTO: Tableau Numérique à base de Wiimote (Fabriquer un TNWii pour 41 euros)

Worth noting, Johnny Chung Lee also designed Head Tracking for Desktop VR Displays using the Wii Remote, and a $14 Steadycam The Poor Mans Steadicam.