[dmm]

I think it is hard coded only because MM assumed that no one would ever want more. That is SO common with programmers. (Bill Gates: "Who would ever want more than 640K of RAM in their PC?") Then getting them to admit the mistake is almost impossible.

I'd love to see planet types be moddable. My programming experience also tells me that it wouldn't be that hard.

The point about the color schemes is a good one, and maybe is the real reason for the resistance from MM -- his artistic sensibilities. Misguided artists are even more stubborn than misguided programmers! Personally, I'd like a hydrogen planet to look like a circle with an H inside.

One Last note: Towing or propulsion of planets has been mentioned before. What would happen if you towed a sodium planet into a chlorine one? Boom! You'd get a salt water asteroid field. Now THAT would require some tough coding changes.