How is this 12" notebook going to fit into the rest of the current MBA lineup? I just can't see this co-existing around a 11" MBA, 13" MBA and 13" MBPs. There's likely going to be a shake up in the overall notebook portfolio.
I could easily see Apple eventually phasing out the other two MBAs in favor of a single 12" Retina MBA, which is a sorta best of both worlds solution. It'd streamline their laptop lineup, and in fit perfectly alongside the MBPs without any overlap. You can get a 12" Retina MBA for $1000, or jump up $300 and go for the entry level rMBP, if you need a little more oomph from your computer.