2016.04.28 - UPDATE! - CONVOLUTED PROGRESS....!!!!
It's been a long time coming.
A very long time ago, I thought it would be a cool idea to design a cage plate that actually followed the profile of the bed floor so that there wouldn't be any gaps underneath... no way to trap water, crud, etc. And would provide a solid crush-proof connection from the upper cagework to the frame/rockslider structures below.
Last night, my machinist dropped off the "prototype" of my idea based on the best information that I could provide (dimensions, angles, depths, etc)
Here's how the clamshell looks:
For a prototype, I was VERY pleased with how accurately it already fits!

It looks like we can pull a few thousandths off the high "peak" areas on the top and bottom plates and the parts will drop together perfectly and squeeze out all the remaining daylight that you see here:
Here's the concept of how it will look in actual implementation:
The convoluted section (which will be welded to the bedfloor) offers a nice 6" x 6" landing pad for the smaller cage plates (which are welded to the cage itself)... given the variability of where the cage lands on the floor, it's good to have a pad with a good amount of "margin" around it just in case the cage is offset slightly left or right of where the convoluted plate is affixed to the floor.
Anyway..... thought you might like this. It was great finally seeing this idea rendered in actual steel. If my luck holds, I should have "final" parts tonight or tomorrow for a second test-fitting.... and then the parts go into production so that I can get 12 more pairs.
-G