I got my Zane up to level 50 last night. I've been running a boss fight in the Moxxi DLC that has a ton of adds, and can be reset without having to save and quit. It's kinda boring, but I got a couple nice annointed Lucky 7 pistols which helped. I can now equip my Redistributed SMG that Wotan dropped on my Amara. I still have to get 3 more levels and some gear, but Zane is definitely a powerhouse now!