Aquarium Artisans in Cincy will begin to carry and or make these type structures - of course it will be demand driven. Making these is not very difficult, tools needed: gloves, safety glasses, rock, some use adhesive to start, chisel/flat screwdriver, hammer, tie wraps, E Marco 400 reef cement or NYOS Cement, PVC small diameter or acrylic rod, drill with larger bit and a good chunk of time. There is also a great BRS video on this as well. The only watch out to make the cement bond effective is to push it in from the sides and not try to do a 'Brick layer method or rock/cement/rock' . Hope that this helps a bit, I have made numerous structures for myself and helped my buddy make about 7 structures for his 280g tank.
Cheers[/font]