It looks like Ubuntu 9.10 “Karmic” has fixed the issues with StepMania. That’s just one less reason to boot into Windows now. 
On another note, I finally finished stepping and making graphics for Raar by Noisia. This song has the second slowest BPM in Tsunamix so far, but it’s no less awesome than the rest. The stepchart will be released with Tsunamix.