I find this fascinating. I would think it easier to heat a die with a torch until orange hot let cool slowly (by burying in sand if possible) would take the temper out, The it would be workable with home shop tools if you had the stuff. A local commercial reloader had something like this done to several dies. His frugal ways would never allow him to spend the equivalent of $50 on a project like that. We use to heat things up in a charcoal grill while cooking hamburgers, then shape on our anvil. That is pretty low tech, The shop I had projects like this done at had many tricks for this kind of project. Ivan