That is a work around for the track ordering problem, but not a perfect solution, there may be cases where a given track is part of 2 or more "albums" and wants to be the first track on one, and the last on another.

It doesn't cover the large data set problem.

2. I am a little concerned about the adding existing nodes method, when the site has a full catalog of tracks (say 2000) that add screen is going to get very full, perhaps an auto-complete field here instead? Similar request to http://drupal.org/node/132082

Glad you liked the thread, did you find any other hints / tips? I'm in #ubercart quite a bit, drop in and say hi

I have a few more bits to do on the site, but hope to have it live sometime this month... will post a link once its live.