Just in case this is helpful for somebody, I thought I'd post it here.
I wanted to make a lot of edits to my blog but I didn't want to go through the web interface, I just wanted to use BBEdit. I wrote these two scripts, the first takes your entries and writes the body out to a file, the second updates the database with the changes.
http://www.estey.com/scripts/mt2dir.pl.txt
http://www.estey.com/scripts/dir2mt.pl.txt
Just make sure you edit the $USER, $PASS, and $DIR variables at the top of each script.
Let me know if these are helpful...
Gavin.