For example, the 5D was at its release stricly concidered a pro camera. Now that it's gone down in price, it's concidered more of a pro-sumer. It's still the same camera though.
Likewise, when the Digital Rebel was introduced it was concidered to be aimed for advanced enthusiasts and some professionals, while now it, and the current generation of rebels, are "entry-line" cameras.
Actually, Canon Inc has always maintained that the only professional bodies were the 1-Series. Canon Inc has never, ever waivered from that viewpoint. Canon Inc has always said the 5D and xxD cameras were designed for "enthusiasts" and the DRebels were designed for "casual users." One former director of the imaging division for Canon specifically said the Kiss (Rebel in the US) was designed for housewives...his term.
Canon USA and Canon Europa (as cases I know of) have marketed the 20D, 30D, 40D, 50D, and 5D as "cameras for professionals who purchase their own equipment." And specifically, they've marketed those cameras to professionals who don't depend on absolute reliability in a camera body (you've never seen a Canon USA or Canon Europa ad of a professional sports photographer with a 5D...but you will see an ad of a portrait photographer with a 5D). They've never marketed the DRebels to professionals.
So I don't think there is any confusion sown by the manufacturers over the issue, and much of the anxiety suffered from feverish forum denizens is because they aren't paying attention to what the manufacturers are saying about their own products.