In reply to niallk:
Yes to Red Burn, then, if there was snow everywhere, I think (without having looked closely at all the actual terrain except on a map) I might try and go left all the way round Meall an t-Suidhe from the Halfway Lochan, perhaps ending up near the Ben Nevis Inn. But as I say that's speculative--it depends how feasible a long descending contour round Meall an t-Suidhe would be.
A different project altogether would be to ski down the back--descend towards the CMD arete then use the long slope down to Glen Nevis. Or indeed go up CMD and ski more or less to the Aonach Mor gondola...