Just to clarify, I'm talking about the refurbished site, not the regular Canon USA site. The refurbished site seems to only list a limited number of lenses, ever. For example, the 400mm f5.6 prime has never shown up on the site. Same with the 200mm f2.8 prime. I'm still waiting for the 70-300mm L to show up, but it hasn't yet (perhaps because it hasn't been out very long and isn't a big seller?)
But, the lenses that do show up on the site have been pretty consistent and are listed regardless of whether or not they are in stock at a certain point. They will list a lens for months and months and it will go in and out of stock, but it's unusual for a lens (or camera) to be entirely removed from the site.
I wouldn't know what to read into it, if I were going to read something into it. The removal of the 70-200 f4's, coupled with the recent rumor of a new version does have me wondering though.