Past few weeks went mostly while rewriting small part of code. It really wouldn't have needed to take that long, but I always got really tired after just looking at that code for a few seconds :)
Anyway, now messages are parsed in 256kB blocks (maybe I should make it configurable), so large messages don't eat all memory anymore. Maildir support seems to work with the new code, though I haven't tested it too well yet. mbox is currently broken.
If you want to test it, dovecot's CVS is available with rsync. I don't think I'll bother setting up pserver since that CVS has also other sources that aren't public.
With rsync you'd do it something like:
# initialize new cvs repository (do it just once) cvs -d ~/cvs init
# update cvs repository rsync -avz --delete dovecot.procontrol.fi::dovecotcvs ~/cvs/dovecot
# checkout the sources from your cvs repository cd ~/src cvs -d ~/cvs checkout dovecot