Well, it's been a couple of years since I started this thread and, at long last, I can finally say that I have gotten away from foam and OSB entirely! I am just in the process of finishing up my first Roxul / "Larsen Truss" style enclosure. I'm very pleased overall, although there are a few tweaks to the wall system going forward to make it more time/material efficient.
Many thanks are owed to Jay for inspiration and encouragement and Ben at Fire Tower for his insights.

Pictures and details to follow, as I have time...