Because who doesn't love racks?
There are a few options out there and I thought I would collect them all together since I'm trying to figure out which one I will buy. I don't know how to weld nor do I have equipment or I would build my own.
It turns out that many options are from Europe where the little GS500 is more popular.
SW-Motech has some options. You may find a distributor in the US. Twistedthrottle.com may be able to get you whatever you want?
I'm guessing it would be around $200 for a basic setup. There is no vertical component like that found on the Ventura system. You basically buy the base rack and then an adapter plate. Then you buy a top box and secure it to the adapter.GS500EGS500F
Hepco & Becker offer a full rack system. You can set your GS500 to be a serious mini sport tourer with big-name hard cases like Givis. One of the forum members here has or had a setup like this on a GS500F -- very cool. You can also use only the tail rack portion -- the system is flexible and allows you to remove the side rack component without removing the tail. It's very difficult to find in the US. Your best bet will probably be contacting a store like Twistedthrottle.com and seeing if they can get one in for you. I don't know the cost.
Ventura has what looks like a nice system. There is a vertical bar you can use to secure stuff on the passenger seat as well as the horizontal rack part that extends over the back of the bike. They really push the combination of their rack with their packs. Looks like it would be $230 or so? Expensive but one of the best options.K1-K4 E modelsOther Suzuki bikes (lots of 500 models listed)
Renntec is another UK manufacturer. They offer two styles, both for about EU 70. This is actually available in the US for $130. Click the second link. The web page is heinous, but you should be able to find GS500 listed there. http://www.renntec.co.uk/iqs/cpti.501/suzuki_gs500_accessories.htmlhttp://www.revsperformance.com/renntec/sports_racks.htm
Five Stars is another European manufacturer. Again, a little hard to find stateside. This looks very similar to the Hepco & Becker. Price looks relatively low (for a rack system) at EU 110.http://www.getgeared.co.uk/core/media/media.nl;jsessionid=0a0104451f43042b3cca52c44274bd4ad56e62d21e89.e3eSbNmQaheLe3qNbi0?id=2362&c=731612&h=248a8e2fc7fa0e64e341
Suzuki had an OEM rack that is now obsolete. It was available for 01-02 model years. You may be able to find one on ebay. It was around $85 new.
I'll continue updating this later. Please chime in with what racks you have used and how well they have worked out.