I called DELL and they told me that this was a scam, and that they would not be honoring any of the supposed deals on the 4600 that was posted above. The rep said Dell was aware of this and that someone had broken into their system and had created the false web pages.
I don't buy that part of what he said. I think someone on Dell's part just screwed up their own web pages. It wouldn't be the first time a web page at Dell changed mysteriously at some point.
I challenged the Dell rep that if this deal was bogus, then the deals that Dell had offered in mid September for the 400sc's must have been bogus too, since it was impossible to even buy a 3.2ghz processor at the price the 400sc's were going for. He acknowledged that Dell had made a mistake there too but decided to honor it.
He wanted to know if I found this information either at techbargains or anandtech? Apparently, Dell watches both of these sites pretty closely. That's probably the reason the deal got shut down so quickly by Dell and so abruptly.