I don't remember how the tileset information is stored in the level, but I'll keep it in mind. You may be able to get away with using higher numbered blocks files and levels using them, but I wouldn't bet on it..

Actually, this would have nothing to do with the tileset compiler at all.. it's a matter of JCS94 and JJ1 supporting it

found one more example of the level->picture thing I made a while ago and have lost most of the source to since..: http://www.princeton.edu/~mspear/level2-000.PNG