No one has answered MY question: Has there been an IRRA angle winder race held anywhere? With the obvious popularity of the class, one would think every IRRA region would be racing them.

To my knowledge NO, but they do race the D3 version in California. Conversely, I also don't see an overwhelming migration to Stock Car. Other than a couple of Retro East races, the majority of where it has been run has been in the chastised RMMRA.
Personally, I don't see why the IRRA needs to be everything for everyone? I also don't understand why, if it is in the rules, people see the need to try to incorporate the class into a program? FWIW I wouldn't loose any sleep if either class disappeared from the rules and everyone focused on the core classes of F1, GTC, and Can-Am.
To quote Ron Hershman from another blog in reference to USRA racing:
"The Group 10 class was the largest when Wedge bodies were allowed to run. The year we went to Stock Car bodies started the decline in Group 10 racing, then the motors made it worse."
You would think we would have learned something from the past and not even entertain the idea of running stockcar?
Larry:
I would have thought you would have been all over some JD class addition?