Because of the EverDrive, we already have ROM playback. And an album has come out with music of Freezedream, thanks to the techniques of little-scale and coders (shiru and alone coder to mention 2). I think that until I get a Nomad, the native tracker can wait, because the Genesis isn't really very gig friendly yet (compared to bringing out my Asus Eee PC which is very light and battery powered).
However, I will give donations to the cause if anyone wants to sacrifice themselves to making physical Genesis carts that let you natively compose and backup compositions on Genesis/Nomad hardware.