[John Boath]

Mark,
I see two options.
Start with a brake-formed piece and shrink/stretch as you did.
Not sure I see the limitations with your shrinker/stretcher since the part isn't that deep.
There are deep throat machines available. Big $$.

The other option would be to develop a flat pattern; in this case it would be a long gradual curve.
Then create a hardwood hammer form that would clamp the blank in place and fold the flange over with hammer and or slapper.