I bought a custom plate for my Nikon D800 to use with my Ultimate M1 but I would be really interested in a 'L' bracket version, I don't know if this is a viable option. I do have a Kirk 'L' bracket but obviously I've got to line it up every time I use it (if and when I take the U3 off). So, a self-aligning one would be great to keep on and use with my ball head.
This is obviously more aimed at Nick.