I am quite interested in a 12" MBA with Retina Display, I wouldn't wanna be an early adopter for an ARM solution though - there are just too many variables.
I'm not really sure about a fanless Design either since I wanna have the option to "work" with it rather than just browse the web and listen to music. If they feature an all new revolutionary Invention in terms of cooling I would probably wait a weak or two for the internet to put those new machines through their paces before pulling the trigger.
Intel is the one making the fanless Broadwell processor, and they've already shown off fanless models. It has a lower thermal output because it's based on the 14nm process.
Please don't tell me the only way to get things done is with inefficient hardware.