Thread necromancy. This gets a +1 from me, yep. Moving the sample / instrument editor to another display could help.
Would be handy to be able to float the Tree View too, so that I could move it to the secondary display (AFAIK, the Tree View is currently fixed to the left side of the MPT window). I like seeing as many channels simultaneously as I can, and moving the tree view aside would help there (and also saves the trouble of constantly having to shift the tree view forth and back to view it or the channels).
Which reminds me, the scalable view (hi/med/low channel zoom) is handy for getting the big picture, but editing in Lo detail mode is difficult because you can't access the volume / command columns. How about a display mode where the current channel (where the cursor is at) is displayed in full detail, but all the channels around it are displayed in low detail? Would it look confusing?