Modding terrain

[djpsychonaut]

Hi, my apologies if this has been covered before. Is there some way to mod Warlords so that the map either:

a. never creates ice, tundra, or desert
b. ice, tundra, and desert are actually improveable even without resources and yield some amount of food, shields, and/or coins

Also, is there anyway to mod the game to allow the workers to terraform a square into a different kind of terrain? This used to be possible in prior versions of Civ and also in Alpha Centauri.

Thanks!