GSXR 600 / 750 rear shock with attached reservoir.  Looks to be clean and in good working order.

$25 + shipping. 

Same bolt hole size and width (30mm) as the stock shock, top and bottom.  About 30mm longer than the stock shock.  GSXR shock and GS500 stock pictured.

so how much of a rise would this give our bike?

I would guess about 2".  Filipe_500 says his bike has this shock.  He has different rear plastics and seat so it is kind of hard to compare to my bike that is basically stock.

http://gstwins.com/gsboard/index.php?topic=42228.msg474861#msg474861