From the front it looked almost identical to the 40D as well. It wasn't specifically marked 50D - it just had a flat black panel where the silver model number usually goes. The Direct Print button above the rear screen has taken on another role as the direct to Live View button, and the buttons below the rear screen have been reshuffled with the loss of the Jump button and the addition of a Function button.
Another noticeable difference was the silver top dial, as opposed to black, though this may simply be a feature of it's being a pre-production model. We are hoping to see shipment end of October at the latest, hopefully earlier in the month than that. We are already taking 50D preorders on our webstore and we will keep you informed of further news & developments.
And Just a reminder, Photokina begins two weeks from today. Historically, many big announcements come at this show, so if there is still anything new from Canon to be announced, expect it around that time.