If Google built something to run over MS then I think they'd have big problems with MS. Building a browser is one thing, but building an OS skin is another thing altogether, I suspect MS would demand some kind of licensing fee.
As for the payment solution accepting adult, I can't see why they wouldn't - they have no problems with adult bidding for terms in their sponsored links. Then again, Google doesn't allow adult sites to join their AdSense scheme so who knows...
