It's also a real pain to design, being a funny shape with all those contacts. There is also the metalwork for the brackets, they will probably require special cutouts.
As someone has said, we won't get any cheap deals on prototype boards. Then there are issues like quality control of the gold plating.
The military have used Eurocard-based VME equipment for over 20 years, because of its reliablity and robustness. Indirect connectors like DIN41612 are the only way to go. It's even possible to replace the connectors if they get damaged.