As it happens, the cost of $175~$200 for a 6" e-ink panel has been pretty firmly established by a number of sources. It's hard to get a firm number, because PVI (who makes the panels) puts everyone and their kid sister under a Non-Disclosure agreement before they'll talk pricing at all. Then there's the whole volume discount effect which makes a firm number that much harder a target to hit.
At a guess (and that's all I consider it to be), the remainder of the Sony Reader's hardware is probably well under $50.
You're correct that the simple fact that something was discussed doesn't mean the outcome of that discussion is necessarily true. But the converse also applies: just because a given person wasn't party to a discussion doesn't necessarily mean that the discussion was baseless.
In the case of the forum, the discussions are all at least still here.
All that being said, I have to agree that I don't believe that 50% of the Kindle's price is tied up in Whispernet -- neither hardware nor EVDO access, nor both. Amazon's been eating shipping on physical books for years now, the delivery costs on e-books, particularly at the kind of bulk rates you
know they have to have wrangled out of the provider, has
got to be minuscule by comparison to the shipping costs.
