Once upon a time, there were some people brave enough to try running Qtractor on the 64studio Linux distribution, a flavour specially targeted to the native AMD64 system architecture. Frank Neumann and Dave Phillips were among them.
I think Qtractor has reached a fairly stable status, after some small changes and fixes. The major fix honorable enough to mention deals with MIDI track mute/solo switching. It is now working as expected, after lurking and annoyingly unfixed for quite some time. Disparate session sample-rates are also subject of a suggestive warning message and then tentatively converted.