Twin wall suppliers & Texas Red Cedar - Advice please!

The concrete curb for our greenhouse foundation is getting poured this weekend. It will be 10 ft by 16 ft.
Does anyone know of a twin wall polycarbonate supplier in the Houston TX area where I can buy out of their warehouse, load my truck, and drive it home? It seems silly to pay freight and crate charges when I live in the 4th largest city in the US. I've been searching and can't find it anywhere.

I am considering using Texas Red Cedar, which is supposed to be aromatic cedar, for the framing. We will used treated lumber on the base against the concrete curb. Does anyone know of a good reason not to use aromatic cedar in a greenhouse?

I live in a very hot and humid climate and am concerned about wood rot, so considering the Texas Red Cedar.

I primarily grow hoya and bromeliads. I understand the bromeliads definitley don't like water from treated lumber dripped on them. I will also overwinter some large plumeria and other tender tropicals.

Thanks,
Susan

Can't advise on the pros and cons of Texas Red Cedar, but here are some possible leads on polycarb sources near to you:
http://www.switchboard.com/bin/cgidir.dll?cid=346&MEM=1&LNK=80%3A4&PR=133&QV=02A60E8145A25641FC303203O01A60F8145A25641FE303203O03A22B3DACA2564149303203&KW=Greenhouses&T=Houston&S=TX&Z=&ST=2&image1.x=24&image1.y=9&SD=10

http://www.switchboard.com/bin/cgidir.dll?cid=12055&MEM=1&LNK=80%3A4&PR=133&QV=02A60E8145A25641FC303203O01A60F8145A25641FE303203O03A72B3DEDA256418D303203&KW=Greenhouses+Manufacturers&T=Houston&S=TX&Z=&ST=2&image1.x=12&image1.y=6&SD=10

and here are some Texas-based mailorder sources of greenhouse materials and supplies:

http://davesgarden.com/gwd/advanced.php?state=tx&country=XX&category=60&search_text=&sorter=company_name&submit=Search

I see no reason NOT to use red cedar and lots of reasons TO use it! It's good against rotting and in my own personal use, has never injured a plant.