[VM] folder list & jumping between folders

[Kyle Farrell]

Does VM have a way to show all folders/buffers in a frame or buffer?
I'm finding I'm using more and more virtual folders, and switching
between them via vm-switch-to-folder a lot.  What I'm missing is
holistic view of all folders.

What would be great is having a view of all folders listed in a frame
or buffer.  Maybe even speedbar integration.  Bonus points if it could
show (#unread/#total messages) in each folder.

Is this a solved problem?  I've got a feeling someone has done this
already.  Or maybe it's not a common problem: how do other users
work with many virtual folders?