I have a real nice treeview that I started hacking up for this kind of task.
Attached is a 'proof of concept'. It needs to be rewritten so I can be subclassed for any purpose.
It can support drag and drop.

I settled on this one because it can run under Poser Pro Pack.

I haven't worked on it in some time. I have alot of other projects I working on right now.
I want to release it either GPL or Lessor GPL.

Let me know if you're interested in working on such a project.