My ave Joe's math:
FF sensor in compact body(like RX1) + pancake fast prime lenses(14,16,35,50,85,135, and or 200mm) = BIG SALE
Only I'm guessing the math gets harder than we think, since it involves creating on chip AF systems that can work with FF DOF, and complete line of lens that gets complicated with size vs. performance vs. cost trade-offs. And finally how big is the market that would pay for it? Sure I'd pay for it, and likely many people on this forum would pay for it, but we aren't the average causal photography population. So would it pay off?
Still I hope someone gets around to it. At this point I think Sony is the most likely candidate. Fujifilm could do it, but they seem to be focused on expanding their crop sensor lenses for now. Canon and Nikon have the resources to do it, but it's questionable if they will being fairly conservative companies.