Well I don't know how you'd go about making a bonafide map editor, since all the maps are 3d meshes, but if you can do it more power to you. :)
I am sure all the information available is accurate, it just may not be the full picture because, as you said, the authors of those tools have stopped working on them. You may want to try to talk to magnusll (
http://www.lucasforums.com/member.php?u=150984). Usually I'm averse to name-dropping, but magnusll has recently been working on some similar tools and as such I can't think of anyone else who might have the kind of insights you're looking for.