Seems that bending pipe isn't as difficult as it seems nor does it require expensive pipe bending equipment.
I found this web page by a clever guy who explains how to bend pipe with simple shop tools.
There are even charts of jig radii for desired outside radii.
He also has a calculator for drawing large ellipses (might be hard to find a protractor big enough for a bending jig).
And another page where you can calculate, download and print cutting patterns for mitering the tube ends before welding.