I just revisited Renoice. The last time I checked they were on version 2.0 and at that time all old-school formats mod,xm,it sounded terrible. Well.. I tried 2.8 and it still sounds terrible. It's a beautifully tracker but I can't do old-school stuff. (I know there are on 3.0 now but I don't think there will be much difference in mod support)
However OpenMPT (modplugtracker) plays every mod,it,xm I have exactly like my miggy does. It doesn't look pretty but it sounds and play's very well. Maybe you can create a linux version.