I was thinking the same thing. It wouldn't be too difficult to machine the frame and give it an Elevator/Docking Station look. And the wiring should be rudimentary, right?
It wouldn't be too difficult to machine whatever you needed to, but the ability to adapt to slightly different port positions while getting a clean docking / undocking action will be the order of the day. That is quite difficult to achieve bearing in mind the connectors involved.
The problem, and you can search for who posted in my thread a long time ago regarding this, seems to be the fit of the ports and the longevity of the lever fit arrangement. Thing is of course, on a machine like the MBP which is built to roughly Dell standards of quality, ports can vary very slightly in their position.
I'm sure a jiggle here and there and a few re-dockings every time will solve the issue. But if the posts are anything to go by, it would be just as quick to re-attach all the cables manually once some play develops in the Bookendz mechanism.
With the Dells, Lenovos, HP's and Sony laptops I've had / have, I just push it into the dock. It's frankly silly to be levering stuff around and making sure I have the laptop sat just so.
The asking price is a little over the top, especially as the $300 Dell D/Dock has a second optical drive port, dual monitor output, a half-length PCI slot and docks/undocks in one clean movement, but come on, it's an Apple related product.