Speaking of Lua and text editors, I've been keeping my eye on this for a while: http://code.google.com/p/textadept/
I would love to have an Emacs-like editor (scriptable, multiple buffers, no GUI or menus) that 1. used Lua instead of elisp, and 2. had a vi-style modal keyboard interface rather than primarily chorded keys. Oh, and not being tied to GTK is nice - I like being able to use Emacs in shells, from screen/tmux, etc.
One of these days I might give in and write one, but I've already got too many projects going.