I finished this epic thread last night, and I've gotta say - Thank You! Thank you to Paul, for your hard work, and willingness to share it with us. To E*clipse, for adding a slew of interesting and relevant technical ideas. To thingstodo, for a comprehensive test program. And to all the other posters who chipped in with ideas, thoughts, and advice.
Bit of background - I spent almost 30 years working at a defense company, in a group that designed and built both control systems and power converters. I had the privilege of working on several large inverter and converter programs. Most of the time I was the program "lead," which I always interpreted as serving the team by working to get the right resources at the right time, and by running interference with management so the really smart guys could get their work done. This project was one of the best examples of a tight technical team working together I've seen.
Next step for me is to go find schematics and source code. I have some questions about some of the design choices that were made, that weren't directly answered in this thread (believe it or not!). But I want to understand the design a little better first - the answers may reveal themselves.
Looking forward to building one of these myself, very soon!