Retina will NOT make it to the MBA until a screen technology comes along that draws less power and is cost effective, perhaps a version of OLED technology? The power consumption of Retina is just too high to make if feasible in the current genome of MBAs. Remember, these are Ultrabooks, and size and battery life trump display features.
IGZO
bit-tech said:Manufactured at Sharp's Kameyama Plant in Japan, the display panels use IGZO semiconductors to reduce the size of the thin-film transistor layer while simultaneously increasing pixel transparency. The result: high-resolution display panels that require a less powerful backlight, for an overall reduction in power draw of up to 90 per cent
My emphasis added. The Retina MBP 15 only needs 22% more battery to account for the larger power draw. If IGZO display technology comes in 25% power savings or more there should be no problem with power consumption.