I don't know if anyone might be able to use this, or not, but.....
http://cgi.ebay.com/ebaymotors/07-Suzuki-GSXR-750-Rear-Shock-GSX-R_W0QQcmdZViewItemQQ_trkparmsZQ7c301Q3a0Q7c293Q3a1Q7c294Q3a30QQ_trksidZp4634Q2ec0Q2em14Q2el1262QQhashZitem20ac091800QQitemZ140325230592QQptZMotorcyclesQ5fPartsQ5fAccessories
The piggy back stuff needs massive mods to fit. I am talking hacking off the shock mount and re fabbing etc types.
Stay with kat 6/7, in fact I hate the GSXR pre 95 ones pretty much, one of those on the back of the red bike made its chain hit the frame on the under side.
It rode great, but was a PITA in all other aspects.
I dunno, if racing it, yea OK I can see the GSXR being good. Miles and longevity are secondary there.
Cool.
Buddha.