You could take a look at Luggage. It has many default filters (PeriodicTable optional), among them a filter for equipment sets. I'm not sure if it is compact enough for you. You'd have to cope with one more (short, depending on your bag setup) bar on your screen, but with the right bag setup, you can selectively show potions, gear, quest items, anything you can filter.
Unfortunately, it still has some bugs that (very rarely, I experience it about once a month) will hide half your items. If you try it out and find a way to reliably reproduce it (or any other bug for that matter), let me know, please.