I would love to get hjkl movement and some other vim-like keybindings, like / for search, if possible. I'm aware of Dactyl's thunderbird project, but it looks like it's in alpha. Similarly, Mutterator looks like it's not being actively developed anymore, and doesn't work with Thunderbird 7, which is what I use. If I could easily edit thunderbird's keybindings i think I could just do this sort of thing for myself.
I'm running Ubuntu 11.10, by the way.