Even though you'll get less domestic upgrades, between a fair bit of international travel and short hops in jungle jets and other commuter planes, that probably won't be much of a problem for you (since they are *domestic* upgrades).

Given your preference for upgrades on any fare, there's only one answer ... AA. Of course they won't get you directly to the destinations you desire, but they can get you close, then pick up another OneWorld carrier. For instance, for Australia/Asia, one strategy would be to fly AA over the Pacific then cash in miles for an award on CX to your final destination in Biz/First ... the best of both worlds. If you're only shooting for the 50k tier, that really won't hurt you too much in earnings anyway ...