Something I found while googling "WYSIWYG Game Editors".
http://www.stonetrip.com/what-is-shiva-3d.html
"ShiVa Editor is part of the ShiVa3D solution designed to create 3D games and application in a fraction of the usual time.
The WYSIWYG editing software is the glue between artists and developers providing a fast cross-platform production pipeline."
http://www.youtube.com/user/ShiVa3DEngine
Develop games in your browser. Powerful, performant & highly capable.
Is that Javascript? looks interesting
It's Lua.