I don't know about Atlanta, but here in Jacksonville there are at least two tubing companies. They do it all from small low duty tubes and hoses, to full industrial plumbing. Both are located in the industrial district of town.
I am sure you can find one up there. Start out by looking for a hydraulic supply company. They should get you what you need.
What are you going to do with that? Sounds like it would make some neat exhaust pipes.