[Brooks]

My very casual observations of kids that've made it into Game-making suggest that there was a small fuckload of, well, "garage-banding" involved getting them there - personal projects, be they mods for popular software or stand-alone gear, that demonstrate an understanding of the videogame creation process and the various disciplines involved. If these projects are conducted in collaboration with other humans, some kind of Team Player ability's demonstrated too.

I suspect the Industry rather likes people who know something of the technical ropes, can get along with others, and are motivated enough to express these qualities through their work - make a videogame, preferably a superb one, then make (the relevant departments/employees of) Developers X, Y and even Z aware of its existence.
Failing any responses, you've at least got a superb videogame to feel a degree of pride in. One hopes.

In your specific case, OP, have you shown Harmonix anything supergreat that you were responsible for?