I think I can buy a rear rack and side racks for a 2003 GS500F.  Does anyone know if I can modify these to fit my 2008 GS500F?  This would be an easy solution to my problem.  Otherwise I'll have to build my rear and side racks.  Thank you for your help.  Ride safe my friends.

Since the frame on the GS's hasn't changed hardly at all since it was first made, the '03 racking should fit a '08 no problem.

Someone with more experience with this can probably correct me if I'm wrong, but it should be a bolt-on, no mods necessary.

Obviously you're not in the USA since there was no 2003 model here. (I wish everyone had their location in their profile. Would make it easier for many questions.)

The rear frame is the same 2001 to present.
1989-2000 has a slightly different rear frame due to the different tail plastics.

2003 would fit the same as on a 2008.

Ventura rack? 03 will fit 08 fine. Here's the fitting instructions:

http://www.netrider.net.au/forums/showthread.php?t=121279

Bit hard to see but blow it up have a squint. Ventura are like misers with this info.

Not a Ventura? Frame has not changed over the last 10 years so anything else shd fit OK also.

I have a SW-Motech rack for sale...

http://gstwins.com/gsboard/index.php?topic=60811.0

Very high quality rack from Germany and has seen very little use.

Looking to get about $100 for it.  Not sure of your location, so I'm not sure of shipping costs but it is fairly small and probably wouldn't bee too expensive.