Air China seems to offer Lifetime Platinum after 1,600,000kms (100,000miles) There are also special gifts involved (I'm clueless).

Don't mean to get off-topic but interestingly mileage redemption in Y and C are not much different ie o/w award ticket US-China is 60,000 km (37,282 miles) and the same ticket in C is 70,000kms (43,495 miles). The same with China-Europe flights, example roundtrip award in Y is 90,000 (55,923) and 100,000 (62,137 miles) in C. So the difference between Y and C for a roundtrip award ticket between Europe and China is only 6000 miles!