In reply to newtonmore:
I'm having the same issue at the moment, my friend and i will be out working in Val d'Isere and want ski touring / mountaineering cover for approx 5 months. The AAC are really good but i think they have a single trip limit of up to 90 days, a friend has just told me that you can extend your rescue cover for an unlimited time if you register your address in France with them - am going to give them a ring tomorrow. Have looked into Dog Tag too, they are considerably cheaper than BMC but not sure about their policy wording. Will up date you when i find out more!