I know AAA/Clavey uses 6063 because I just bought $250 of the stuff at $6 a ft for my big boat.
DRE says they use 6063 here http://www.downriverequip.com/asp/frames.asp
I know Rowframe uses non-anodized 6061 sched.10 as those are the tubes i'm replacing on my mini max frame. got enough for the whole thing for $50! I figured I'd try the stuff to see if it marks my boat/hands less etc. Gary told me the pretty much all the anodized AL you see is 6063.
I'm certainly not an engineer or the champion of 6063 pipe, I just wanted to send along an FYI- wish I saw it myself before I bought the $6 stuff.