Not sure about the cam action. Haven't seen one up close.
I'm not sure about the Anthony's, but a few of the Centurys had a 2-section bed that extended backwards, similar to a field camera set-up. The rear standard is mounted to the inner extension rails/frame. The front/outer frame sat on the camera stand bed.
A long bed, unless it's retractable or modular, will get annoying when you're using shorter lenses. Assuming a 300mm lens as the "regular" lens, at 1 to 1 you'll have 600mm (24") of extension. If you have a 36" bed you'll have 12" of bed poking you in the chest while you're trying to fine focus.
I have this problem when using my 210mm on my 8x10 Korona and it can be aggravating.