You may know about the openblack project, which aims to recreate the whole game engine. There is a issue about LHVM but I don't know if somebody is working on it.
I was working on a graphical debugger for CHL scripts, but I've suspended the development waiting for more inspiration (but a text mode debugger is complete).
At the moment I'm working on a new land editor, but it is in a very early stage.
I haven't thought about a collaboration yet... Is there something you would like to do?