Hey,
maybe your shortcut name is not matching the regular expression used to find thunderbird icon - thunderbird[^/]*.desktop.

You can try to run file:
http://cloud.github.com/downloads/lpiepiora/docky-thunderbird/update-badge.py
with for instance:
python update-badge.py 5 or with any number > 0, and see if it changes the number of unread messages on your TB icon? If it doesn't please can you show me the output?

Hmm, that certainly sounds like it could be the issue. I ran the script with no output and no number update. I also modified the script to look for "Shredder" (the thunderbird 3 codename) and still no go and no output.

I believe it should look for the thunderbird anyway - that's the shortcut name, and unless you've installed TB manually it should be that name. But you also should see the output anyway (unless you have nothing on your Docky except for the TB). Ok, maybe the stupid question, but are you using standalone docky (https://launchpad.net/docky) or just Gnome-DO skin?

Not a stupid question at all, and possibly the issue. I am using the gnome-do install from the Ubuntu 9.10 repos, so it's the docky skin.

Try standalone Docky to get more advanced features ;). I'm closing the issue then.

:-(

I'm sorry, but it's technically impossible to have that feature in the gnome-do skinned version.

No biggie. I'll be updating to Lucid soon anyway. I have it on my test machine, guess I could just upgrade early. Thanks for all the help.