Hi TCB,
I'm sure you will find a lot of valuable knowledge on the forum, I know I have had a lot of food for thought!

As far as your question goes, it occurs to me that what you are proposing sounds a lot like a sort of timber framed Larsen truss. It seems like it would be much simpler to apply wall and roof trusses to your timber frame. It seems like the system that you are proposing would exponentially increase the time and complexity of timber framing a given building.

Are you sure that a plastered enclosure would be hard to upkeep in your area? I'm not sure on the area of Texas, but if it is the right climate it might be worth another look.