Following up on myself...
OK, so I found the bits about this being courier specific (which I 
highly suspected), and that makes sense.  But I also found a few other 
people looking for similar functionality and a hint that it should be 
doable as a plugin.  The question now is, is it done as a plugin, and if 
it isn't, where is the best place to find plugin development information 
so I can take a crack at writing one?
-David
David Powers wrote:> I am moving a courier installation over to Dovecot and I am wondering if 
> there is a way to set Dovecot to automatically move purged items to 
> trash (under IMAP).  Additionally, is there a way to automatically 
> delete old items from a Trash folder?
> 
> -David