I haven't, I can only get up to Mojo King Bee. My little brother on the other hand, has gotten up to Stage 9 (He would be on Stage 9, but a scratch in the disk prevents us from playing 9 or 10)!
We are still in shock he beat the Sambone Trio, no doubt the hardest Master Mode level. It took 400+ tries...
So, any Gitaroo Man masters out there?