order of mailboxes in browser?

[Bob Self <bobself@xxxxxxxxxxx>]

I have 28 subdirectories in my main mail subdirectory. I'd like to get the
high traffic maildirs to be at the top of the list so I don't have to scroll all
of the way to the bottom where most of the busy lists seem to be (vim, ubuntu).
Is there a way to force the order of these directories other than 
alphabetically?

Or, can you make the up arrow wrap around to the bottom of the browser list?

thanks,
Bob