I've read a ton of posts that complain about managing large amounts of rigs and I have that problem too. Maybe a simple solution would be to allow the user to create custom folders that he could move rigs in and out of. I'm not talking about a "criteria" based filter, but a real folder just like in a file system. That way, it would be easy to say, go to all of my Marshal rigs or see my experimental rigs.
What do you think?