This has been thought of, last I checked it was called the Clone Engine, and in production on Smashboards. I'm not really sure what its status is now though.
I'm looking for a GCT editor for the Mac. I don't get a PC until sometime after christmas, and the Code Editors on the Wii just keep on freezing when I try to make the GCT file. So can somebody redirect me to something like this?
Or if not, I don't know if this is the place to ask, make a GCT file for me using the Latest Brawl+ nightly build but with all Alloys and Wario Man playable?