The biggest issue here is that developers who didn’t order one during the keynote won’t be getting their retina MacBook Pros until 2-4 weeks from WWDC. Yes you can enable HiDPI mode on a 27″ and get a pixel doubled 720p experience and yes you should have been including @2X artwork since the writing was on the walls, but it’s not a simple matter of recompiling. You need to test on real hardware.
I dream of a day where Apple has a developer store that gets items a day or two before the public store. There wouldn’t be any units reserved for developers, they would just get to place their orders before the general public. It’d be interesting if Apple started requiring shipping binaries to get many of the developer perks.