I wanted counts of unread emails onto my dwm status bar, and could not find any nice way to the those from thunderbird. With a few pointers from the intarnets, I wrote this quick'n'dirty perl script to get the info in a reasonably interactive and resource friendly manner.
It abuses tail -f to read the .msf files under $HOME/.thunderbird/*.default (note: new boxen won't appear in the results without restart of the script).
The script is probably buggy and there most likely are cases where it fails dramatically, but seems to work well enough.