Hi Jon,
I was thinking about your picture of your roof and what you said about French and American timber framers.
Your photo is actually very similar in nature to what I have seen in old American books on timber framing from the late 1800's, particularly when regarding industrial construction. The use of purlins fully crossing the principal rafters, incorporation of metal hardware when convenient, and a relatively simplified joinery.
I'm supposing that around 1900 the charpente traditionelle and American timber framing tradition would have much closer to being analogous. The French system, because of the conservative nature of the Guild structure kept on a fairly unbroken track with an eye toward function. The Americans followed a much more chaotic path of abandoning and then rediscovering heavy timber construction. This has led to practices which are largely purely innovative or hearken back to older and "purer" forms of timber framing.

I may be crazy, but your picture got me thinking. Nice framing by the way, it would be interesting to see more pictures from over there if you have them.