yeah, this has been done in many forts. Copperblazes has an axe, Orbinches has a VERY cool dragon. Others that i cant think of the names of.. God i suck with names There was a cool one with a tree.
You can color one tile at a time with bridges. you can make them out of any color stone, metal, or glass. You can also color one tile at a time with ropes. you can make them out of any metal or fiber (silk, ropereed, pigtail), and you can dye the fiber at a dye workshop.
this gives you a lot of colors and textures to work with. The above-mentioned nameless fort with the tree also made use of various traps and pressureplates to create additional colors and shapes. you can actually do some very creative and beautifle stuff with the existing system.
but yeah. formal mosaics might be a nice bloat too.
edit: walls can be colored by replacing them with windows, doors, floodgates, etc. you can use any color of stone, metal, or glass - depending on what type of structure you are building. most of these things block room boundries, so are fine for interior fortress walls or specifically designed decoration areas. dont forget to intersperse actual supports.
also, you can even engineer flashing neon-signs with carefully built gem windows.
[ September 04, 2007: Message edited by: puke ]