Don't forget Conkeror, something like an "Emacs-erator" but without the whole Firefox, using xulrunner only: http://conkeror.org

Its keybindings resemble the ones of vimperator in some respects ("f" = follow), but reminds you more of emacs regarding things like (mini-) buffers, M-x whatever, ...

// Edit: Just stumbled upon another one: http://redmine.philpep.org/projects/show/cream using C, GTK+, WebKit, vimperator-like interface