Hello!
> Where are the effective and comfortable ANC headsets that will stand up to
> being used by a professional pilot on ten or more legs per day and 1,000
> hours per annum in temperatures ranging from -45C in winter to 40C in
> summer?
I don't know where it is, but my Sennheiser HMEC 25 something (ANR) must come very close to your description. It must be over 5 years old now and apart from recharging the batteries every now and then and replacing the foam thingy over the microphone, it still looks and works like new. It gives excellent protection in single- and multi-engine piston aircraft and is light and comfortable even on long days with and without (sun)glasses (my record is an 8:20 cargo flight in a Cessna 404). The only aircraft for which the noise reduction was not adequate has been the Metroliner, but this is a thing of the past for me by now. In the jet, I don't even bother to turn the ANR system on.
What I would consider as an alternative is the Telex Airman ANR 850 that is even lighter and needs no battery, but is really not quiet enough for propeller aircraft.
Greetings, Max