I have seen many sites which have adsense ads different from mine. Just check the attachment, the ads has no scroll and also there are two adsense ads together with no hyperlink.
I think you are looking at a "superuser" - e.g. someone earning a massive amount from adsense, on such sites google gives them a much freer rein on the format of the ads. At this level of business you even get your own adsense contact at google. But as I say you need to be generating megabucks to reach this level.
Dickie Boy