I think it would bring about enough breakthroughs for a lot more than one Nobel :-) But yeah, I'm definitely not the first one to fantasize about being able to correlate behaviors or even just basic bio signs across a big chunk of the population with the medical results.

I even think it'd be feasible to pull it together as a company, since there are lots of immediate potential benefits to using the things that would collect this data. A much better replacement for Life Alert, which works even if you're unconscious and can't press the button. Dieting aids, sleep aids, exercise aids, passive diabetes monitoring. It's a lot to bite off, especially as a startup, but I think a team that knew how to execute on this kind of product could roll out products serially and pull together that dataset. That dataset would enhance each other product in the way that each of Google's views on the internet (DNS traffic, browser feedback, analytics) help its core product. A hell of a defensible advantage. Not sure how one could convince that company to give up its crown jewels for the sake of medical research, though :-)