TCB,

I think maybe a good fit for the sort of scenario you are looking at would be an industrial revolution era German and Swiss (My research suggests it may have originated in either Bern or Basel, or just across the Rhein is south Germany) sort of light timber framing. For good pictures, go to google.ch (swiss google) and search the term 'Riegelbau' then look up images (it should default to English, but if it doesn't 'Bilder' is the German word for pictures). This is the sort of framing that's most common at least in the Swiss Canton of Bern today, an extraordinarily efficient building system.

I think you could easily adapt this to work with your system without creating tremendous waste and redundancy. Basically two such light frames built together.

Actually you have really got my mind working, and possibly led me to just the answer I have been looking for to build a timber framing system that is super efficient, yet can still incorporate the sorts of features people want to see. I'll have to open up sketchup and play around with some things...