I don't think anyone in this country has any everyday experience of your problems. It sounds as if good ground clearance would be an important aspect to consider and low profile tyres should probably be left on the options list. I don't suppose you've considered a Land Rover or a Toyota Land Cruiser? A very powerful air-conditioning system would also be very useful. For their size, both cars are not huge on the inside but that appears to be largely down to the large crumple zones especially at the front. These are things you never knew you needed; that is until you really do need them. I have had a number of FIATs over the last 20 years, from 128 to Uno Diesel, from Mk1 Punto to Stilo and Panda Multijet and there has been steady improvements to quality. However, I for one would love to know how whatever you buy stands up to the demands you place on it. Let's face it, if it can survive being driven in the kinds of conditions you describe then this country should hold no fears for it.