Well, the problem would be creating a Rousseau style nature dome, without mobs spawning in it during night. Torch light seems to be a different color/intensity than sunlight. It'd be nice if there was a "super torch" that gave off sunlight, but obviously without the ability to burn mobs.
I'd love some different colored light. As it is, your best bet is Glowstone, which is light level 15 and doesn't create the problems that lava and fire do. Alternately, use Jack O' Lanterns, since they fit in anyway.