Not happening
"Let us not forget that a long time ago Bill Gates reckoned the kitchen would be the natural environment for the PC."
Ah yes, but only someone with the head buried that much into his rectum like Gates would ever say that, those days.
People are asking kitchen appliances to be as cheap as possible and work flawlessly for as many decades as possible without any defect. Given that, who, even the most ubergeek of us would buy any model stating "Vista compatible", or even with anything close to a computer inside ? Prices would be inflated and there would be costly maintenance each 2 years minimum, for what service ? Knowing better than you what milk or what butter to purchase ?
MS has already taught everyone to be very suspicious about technology working for its interest rather than the user, so I don't think we'll see home appliances with an OS prior to MS disappearance from the fact of earth.
Even car manufacturers are backtracking on that ...