Gearbox Software announced the release of Borderlands 2 on OS X out of the blue for Nov 20th, and it's a game which really takes advantage of PhysX. They may have made the decision to release it based on the recent switch in graphics cards in the new imacs. So maybe this is planned for shortly after the imac release? Just an idea, not sure if it is really that logical... Maybe a little off topic but could be some sign? Who knows, clutching at straws I think...
Source: http://blog.gameagent.com/aspyr-announces-borderlands-2-coming-to-the-mac-november-20/
Source: http://blog.gameagent.com/aspyr-announces-borderlands-2-coming-to-the-mac-november-20/