I've just completed building, integrating and testing the custom DFU programmer in doth Arduino and Energia. I'll publish the board manager JSON file and support packages to github shortly. I'm pleased with how relatively smooth the integration went. I've learned a lot about integrating custom board support packages into Arduino along the way and will do a write about the process soon since I found it convoluted at first myself.
The only thing left to do before releasing this into the wild is to add Linux support and do some minor fixes to the board layout.
If this was crowdfunded for small run of 100 boards, probably priced at $30, would you be in?