The problems with parts getting brittle is a materials problem, not a design issue per se. They could take a standard bike and start making custom parts of identical geometry to solve those problems. Aircraft and rockets can fly in cold temperatures; it's not like everything falls apart.

All in all, it sounds like a group of people who have never ridden bikes or been to the south pole trying to solve the problem. Not to say they shouldn't do it as an exercise, but don't expect to see people bikin' at the pole real soon, either.

From my non-polar hiking experiences, it seems there are places where you're just better off without a bicycle. I could sit here in my armchair and design a bicycle for Mt. Everest, but wouldn't expect to see anyone riding to the top on it, either.