These forums are full of useful information about Mozilla Firebird. Here’s info about a tab extension. I don’t think it lets you move the location of tabs around, sorry Tim!
Here’s my pet peevs about Moz Firebird:

1. Tabs open at the end of the tab list. I like when they open next to the open tab.
2. When you drag a link to the “Personal Toolbar”, there’s no indication you can drop it there (no arrow, indented button space..)
3. I don’t like the image resizing, but that can be disabled.
4. No “Exit with Session” or even session support!
5. No “Up” button to go up a directory/filename.

Still, I think it’ll replace Galeon as my primary browser now that I have nice fonts again