The Current Setup...
Well here's how I ended up installing the cooler, thermostat, brackets, hoses, etc. When I first got the bike, the cooler was mounted about 2" lower. But when I installed the thermostat, I took the opportunity to trim a few mm off the ends of the cooler brackets, so that it could properly fit into the oil-cooler bay. Now it's all where it should be: the cooler sits squarely in the air-flow, and the hoses still allow free access to the oil filter.
Update 5th Nov. 2008: Well after having nothing but troublesome oil leaks from the bayonet fittings on the thermostat, I ended up just pulling the thing out and putting in new top-of-the-wazza hoses. I think the problem was there's just too much heat coming off the header pipes, and the hose joints go all hard and start leaking. Can't have that!