I'm going to build a workshop , up in vermont on my gf's parents land. also thinking about building a small one and turning it into a sweat lodge.

After lots of research and a couple of failed experiments, I think I'm going with the starplates for Burning Man 2008. I'm glad to hear you say 8ft struts should work out okay. I was thinking of making them more portable by cutting the struts in half. Once I arrive, I'll use metal plates (I don't know what exactly they're called, but they're flat, with 10 #8 screw-sized holes for connecting timber lengths) to connect them - one plate on each side, with bolts going through the strut and tightened with a wingnut.

If portability wasn't an issue, I'd probably use plywood sheets for the walls and roof, but as it is, I'm planning to wrap a tarp tightly around the outside, and fasten a dark, breathable fabric to the inside with eyelets and screws.