my $0.02:
Just use the DOM tube, it IS stronger, and if designed properly, will never fail.
as far as access to a bender, you have some options:
1. Dish out the cash to buy one and learn to bend stuff on your own.
2. Find somebody who already has one and knows his stuff to do the bending for you.
Personaly, I would suggest the second option, it would cost less and be less headache than trying to do it yourself. The only drawback is that you have to design the entire cage before any fabracation begins.
I seem to racall somebody above offering to do the bending for you...