Unfortunately, we've rec'd confirmation from Motorola that the Atrix HD does not include the Webtop software and therefore won't work with the Lapdock accessories. It's a price issue; it's one way they got the price down to $99 (on contract.)
It's still a very high-spec consumer device, but for those looking for that particular business feature, the Atrix 2 might be a better choice.
The HD Dock is still available for the atrix and you can still use a bluetooth keyboard with the device. Granted, no wirless mouse functionality, but the only reason I use the Webtop Dock was to watch my movies on my HD TV anyway, and the HD Dock still allows for that to happen, so I care only a little bit about this exclusion.