For me the issue is not so much running under linux, but supporting extended range instruments (7+ string guitars, and 5+ string bass), and having scored vocals, percussions would be nice too, one can dream right. Considering that in FoF, FoFIX, Phase Shift, ultrastar etc etc most of the work has already been done it would "only" need a small team of competent coders to hitch the various bits and bobs together. Unfortunately I'm barely a coder and certainly not competent, but most of all I've already mortgaged most of my sleeping hours ...