I actually did an underworld on the shard I am working on, which has cave walls, with cobblestone floor, and a transition I did especially for it which was cavefloor2cobblestone. In order to do that though I had to directly patch the tiledata and something else... I forget now, anyway I hued the tiles a green color, but I did that by exporting the images into photoshop (I also created the transition this way) and changing the hue then resaving them and patching them. I then created scripts in dragon to place them according to a specific color ID. In effect gaining a new terrain type and a new color to place it with in Dragon. (Maybe I should write a tutorial for this sometime?), but I guess what I'm trying to get at is your colors would work regardless if you edit them and patch them.
It sounds daunting I know, but doesn't really take long, and is very rewarding. Heck my shard has a HUGE underworld for people to go to when they die, which opens up the possibilities for all kinds of new quests, etc... and makes my shard very unique. Then again, people are more than welcome to use this idea on their own shards. I wouldn't be offended, in fact I'd be flattered.
I'll probably release some patches to implement the custom tiles and statics I've done. But at the moment I really need to get this website converted to php.
It's insanely taxing on my brain.
