That would be me. I checked every thread that the Search feature turned up for the keyword "Experience", every thread that turned up for "Winter Fantasy", the D&D 4th Edition news page, and the news archive. I came up with nothing. There is discussion of the alleged quote, but I couldn't find the quote itself, or the name of the person who is alleged to have said it. It was always "a WotC rep" or similar.
The only things I could find are repeated on the 4th Edition news page. There, Kevin Wilson is noted as saying that they are not working on a 4th edition that will require miniatures, at GenCon 2006. The Scott Rouse quote that is being discussed above is also given there.
On the "announcements will be at D&D Experience" thing, I think that comes from another Kevin Wilson quote from GenCon 2006:
That stops rather short of "all major D&D announcements will be at D&D Experience".