I've examined the Martin Fleetfoot, the Gretsch Floating Action, the Camco 5000 and owned one of the earliest (bare aluminum) DW5000's, and they are similar to the point of being able to interchange most if not all of the parts.
In the aluminum parts, I even noticed the same casting marks, which indicates that the same tooling was used to make them.
The biggest difference is the logo on the footboard.
Some of the earlier ones used leather hinges, but since the casting is the same and the holes line up, you can take a Martin Fleetfoot and put a brand new DW ball bearing Delta hinge on it. If you're adventurous you can even easily convert one to a chain drive.
One of the biggest changes in the DW5000 pedals over the years is the size, thickness and weight of the footboard. They were breaking too easily, so DW beefed them up.
One of the failure modes was that if the pedal were not adjusted properly, the bottom of the footboard would make contact with the hoop clamp screw and wear out a gouge, which would then be where the part would break.
I'm a fan of the earlier, lighter, smaller footboards, so I have a small collection of DW pedals of various generations where (when necessary) I've swapped out the newer footboards for older, smaller ones. The extra mass makes the pedal just a little more difficult to get moving.
If you have to have a pedal that looks exactly like the one Ginger used, then you'll want the actual Fleetfoot. If you just want to play one that works the same way, an older DW5000 with the radius rod and no floor plate will be indistinguishable.
The cool thing is that even if you find a fixer-upper, DW still stocks many of the parts for these oldies.
Here's one take on the story: http://www.tbrucewittet.com/2011/04/the-martin-fleetfoot-camco-gretsch-dw/