None. I went through this search a little while ago. No one I could find made an aftermarket one specifically for our bike, or one for another bike that was even close. The 2nd Gen brake is unique to our bike so unless someone lucks across one from another bike that fits, we're kinda screwed.
Haha that's the next step I took too. Didn't work out for me to say the least. Stock 01-03 GSXR 600 rearsets don't work even though a few people on this board said they did. The top of the rear master cylinder hits the subframe. So I dremeled enough off to fit, but then the hose from the reservoir gets crimped. Sooo then I got lowering plates and the brake side fit fine. On the shift side however, the shift pedal hits the shift lever no matter what the adjustment was. Basically, it didn't work out. Just letting you know so you can save some money and frustration. Hopefully the 04+ fits better than the 01-03, but I'm not sure.