hey I ran across an ad on another board I frequent that had some SV parts for sale that I'm pretty sure would work on the GS....
Make your own assumptions though..... Mirrors (A Ducati set and a Square SV set) , Front Headlight Fairing with brackets, bar ends, and some turn signals.
http://www.socal-sportbikes.com/xmb/viewthread.php?tid=51545&page=1#pid810663
bump for my buddy Eric....
Says that Square SV mirrors are gone.