So, thinking and thinking as i am want to do. I have a 29er 50 wide single wall Uma rim from Speedway cycles. The original plan was to build this on to a whub for the new bike. Then i got to thinking. Dangerous stuff. Kris Holm has a new 47mm wide, pre drilled, eyeletted double-wall rim available. It weighs just shy of 800g. The Uma weighs pretty much the same, but is inherently weaker due to the singlewall construction. Hmmmm.
Then i thought, at 800g it is unlikely i am going to use either for racing. A duster weighs ~500g, so why have 300g of extra rotating weight. Using the old multiply-by-4 rule for rotating mass, that is a colossal increase in weight.
What about a Salsa cycles Gordo? It is welded and double wall and eyeletted, but at a measley 35mm wide and 700g it is hardly a better compromise.
So now i am thinking of an Edge composites 40mm wide rim. (they are going to be coming out with a neato seat post also) Only issue...it ain't available yet...