If you're looking for something more extensive, these things are everywhere in Dallas, Texas and fairly popular in Phoenix, Az, and Naples, Florida, so calling a few structural firms might be worthwhile.
There are many companies that specialize and build these, and they have it engineered inhouse. Probably the cost would be cheaper or the same if the clients would just use those companies. Here is one for example.
He is like a man building a house, who dug deep and laid the foundation on the rock. And when the flood arose, the stream beat vehemently against that house, and could not shake it, for it was founded on the rock..
