A stand alone autoguider made from parallax components would be cool, all that would be required for others to make the device would be a comprehensive guide and the compiled source. It gets around any custom surface mounted pcb's and the like.
One their more recent proto boards incorporates video output too, so a nifty interface and visual star guide could possibly be used. (ref;
http://www.parallax.com/tabid/407/Default.aspx)
Some food for thought anyhow
I always like pie-in-the-sky ideas.