You have to sign the NDA to get prices, they don't want everyone know about that. In my opinion that is stupid, but this is industry standard.
Small guys like ED usually get ripped off because those big companies don't care about setting up a long term relationship with them.
There are some exceptions though, particularly if the company sells in low quantity through a distributor or directly on their website. TI and Freescale for example let you buy some parts online directly, so of course you get prices this way. Intel also sells a lot of parts through distributors and publishes prices on a lot of their parts. In all of these cases it's probably that big customers negotiate lower prices for huge volumes. In the other thread Grench found Intel's Z3770 costs $37 a unit, taking that as a worst case that's not that bad for what you get and isn't really that much worse than what OMAP3530s cost Pandora early on.
Note that not all Intel SoCs even run Windows, for example Medfield and CloverTrail+ didn't and probably Merrifield won't. BayTrail-T is fine though. If people want to run Windows on a Pandora 2, even if it's x86, I'm sure they'll be on their own.