Pending queue process applied to other folders

I think I might have seen this question before but I can't recall 
where;  with the pending queue changes to support maildirs, would it be 
possible apply the pending queues policies to another folder.

I generally take things  that have been marked with a signficant spam 
level (as scored by spamassassin) and have tmda redirect those emails 
into a SPAM subfolder, which I typically ignore.

Whenever the SPAM folder gets too big I clean it out.  I've simply been 
to lazy to try to do this with a Cron job or some other such method.

Can I use the pending processing as it currently exists to cull my spam 
folder?  If not, would this be a useful addition for some future 
release?

Thank you,
Tony