Glad to see some more action on my posting- I thought it was dead in the water. Sorry Tim for not getting back to you with framing details-- my internet time is spotty since I'm off-grid and don't have a phone line.

My framing is 3x4's 30 o.c. 1' outboard of the frame. My foundation is 18" wide waste concrete blocks, and I built my frame close to the inside of the blocks, so my stud wall bears right on the foundation. The frame is a tall cape w/ 14' posts. The eave studs are 14' 3x4's tied into the rim joist at the 9' level. The joist tenons run through the tie beams on the gable ends, allowing the stud spans to be broken up into manageable sizes and tying the stud wall into the frame. The roof is to be a built-up foam and lumber system-- 3 layers of 3" xps (2'x8' sheets) set between criss-crossed 2x3's. The first layer will be screwed into the purlins, and subsequent layers will be screwed into the layer of 2x3's underneath. That way, I don't need lots of long panel screws.

Some details have changed since my initial planning. I am now planning to put up 4'x10'x1/2" osb sheathing, since my concept of using the shiplap as sheathing and siding all in one seems to be a dead-end. A nice idea, but way too hard to pull off. I am still up in the air about cellulose versus woodchip clay. If I were to go for woodchip clay, I would be using a very light mix-- more like sawdust and planer shavings with just enough thin slip to lightly coat everything. It seems as though a light enough mix could approach the r-value of cellulose and still offer the benefits of clay. I would also be tempted to add some builders lime, as I have had excellent results using plaster made from clay, sand, and regular type S hydrated lime. It set up very hard. I just replaced 1/3 of the clay with lime-- a very nice durable mix. Having a bit of chemical set through the addition of lime might make the ventilation issue less of a problem.

Jordan- I'm curious about your statement regarding infilling behind permanent sheathing. Is your concern that the mixture will not dry properly, at least in time for winter? What type of mix did you use for your aforementioned project? It seems you used no sheathing, just lath with claps applied on top (w/ a 1/2" furring layer).

Render on the outside just seems like a brutal undertaking. I actually planned on doing strawbale walls plaster inside and out initially, but the thought of carrying a hawk up and down the 30' south gable made me think better of it.

I still think the combo-- woodchip clay packed into the 4" stud cavities with 8" of cellulose behind would be a good option. At the very least, I will be filling the area around the timber sill with a woodchip clay mixture. This way I can try it out, and I like the thought that my pine sill is surrounded by clay.

You can see some pics of my frame, including a few of the studding at my flickr site:

http://www.flickr.com/photos/8739186@N04/

thanks for the great replies.
-Devin
Rockingham, VT