Wish I could help, but don`t have a clue where you could find one..
that said..a few years ago I was looking for one also.... until..
I got new brake pads ECM? brand..I scuffed up my rotor, knit picked my adjustment, and I kid you not, I can now EASILY lock up the track..before that, I had to use my best kungfoo grip and it barely wanted to stop..I`m not sure what was the most help, the perticular brake pads I got, scuffing up the rotor or both..but either way, I`m a few seasons into it, and have never touched it again..still locks up the track easy as heck..
I was also exploring creating more leaverage somehow..i figured I could do a little fancy work on the brake arm part right at the caliper, but after I did the above, I scrapped that plan also..
just thought I`d mention this, incase maybe your experiancing the same thing I did..
AL P