Apple is in the late stages of testing a super thin 15" Mac notebook, Arnold Kim at MacRumors reports.

Kim isn't sure if it will be a 15" MacBook Air, or a MacBook Pro. He also doesn't know when we'll see this new notebook.

Apple just refreshed the MacBook Air rolling out new 11" and 13" models with faster internals, so rolling out another new MacBook Air would be unexpected.