As of today, I started the boring task of migrating Qtractor to Qt4.
As one might know, Qtractor is currently a plain Qt3 application, still in alpha stage of development but already functional. At least you can already do some Audio/MIDI sequencing with it, being its main objective.
The Qt3 to Qt4 source code migration will occur privately and slowly, as time permits and probably it will span for more than a couple of weeks I think. So, in the mean time, enjoy Qtractor in its current Qt3 form, while it lasts.