I think that, for the average Windows user to buy it, it will have to be far more "gadgetized". No "buy a circuit board, do some magic to get Windows on a memory card and then maybe get it to work". It has to be ready to run out of the box, configured and ready, probably for a specific application (say, media center).
However, if that's what you are making, why pay license money to MS (probably more than the hardware cost...), when you can just prepackage with Linux for free. The user won't know the difference, as they only see the frontend (say, XBMC) anyway.
So, I think that MS is kind of missing the target, especially if they aren't planning to release an open and free version of Windows.