Ummmm I havent been able to find a code for hyperspeed (breakneck speed or whatev harmonix calls it).
It's really a crutch for me when I play and I don't want to learn to play without it. That's like trying to forget the small amount I know about the English language. (As in I can't function well without it.)
SO if anyone knows it or if anyone knows why it wasn't included feel free to post.