Music Game - Deathmatches

I was driving around the other day and thinking to myself that games like Guitar Hero and Rock Band don't really have a mode where two players can compete to see how they good they are based on each other's skill level.

What I mean is that you're usually given this track to play, easy to extreme, and who ever can get the most notes wins. But I feel that there is a better way to approach this, though on a music programming level, I'm not sure how it would be done (improving and having notes represent those musical decisions).

Anyway, my proposal:
The first player improvs a solo over a blank track. The game then replays this solo back for the other to play.

The clincher, however, is that the player who created the solo has to play it as well. This would eliminate someone just randomly hitting all the buttons to create a nigh impossible solo just because they can.

Then this goes back and forth and both players accumulate points. Points are only awarded if one player is able to play a note while the other cannot. If both are able to play the same note, then both are equal in skill and no points are added an equal number of points is added to both sides.

What do you think? Any other ways to approach this and make the music game scene a bit more interactive?