I know about "mailutil transfer", but it doesn't seem usable in this context. It reports an error and halts the first time it tries to put messages into a folder that has already been created as a "directory" with subfolders.
Did you try various "-merge" options in "mailutil transfer"?
-- Mark --
http://staff.washington.edu/mrc Science does not emerge from voting, party politics, or public debate. Si vis pacem, para bellum.
