Same as with the Motorola Droid, the Nexus One has found a place (at least at one point) on Google's home page. And if you're in an airport with Google's free holiday WiFi (what up McCarran!), at one point you were redirected to Google.com/phone upon log-in.
Personally, I'm not crazy about the precedent Google set with the Droid advert, subtle as it may be. If that space were for rent by anybody (and it may be, if the price is right, though we likely would have seen something else by now), all would be Kosher. But Google cherry-picking its own products leaves a slightly worse taste in our mouth than we had even after the final night of CES. That said, it's their home page, and they can do whatever they darn well please with it.