There is a rail time-lapse system coming soon for under $800 - moves the camera along a track (3' or 6') and triggers the camera. Add on will allow the camera to pan during the time-lapse. (i.e. keep a subject centered as camera moves along the track between shots.) You suspend the track between two tripods.

This is a somewhat different device -- for use in taking star photos http://vimeo.com/12168314 , but seems to also have some time-lapse functions. Don't know the cost on this one.