http://www.standuppaddlesurf.net/
The Super 12'6 is a normal stand up board but it's been rigged up so that it has a mast track that you can put a windsurf sail in the middle. It also has a retractable keel in the middle and all these different attachments. It's really pretty cool.
Read the full article here: http://www.standuppaddlesurf.net/2008/12/17/starboard-super-12-6-sup-windsurf-board-video/