I can help with some of it, but are you specifically in the market to build and not buy?
Reason I ask is that Grizzly and Harbor Freight both make the twisting machines, ring rollers, and the small bender cheaply.
The brake could easily be made, as well as the large tubing bender.
The most expensive part of the tubing bender is the dies.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
"If the women don't find you handsome, they should at least find you handy"
-RedGreen show.