HA! Well, the problem is that it'd be an incredibly expensive program to run. I was part of the group that built the 2012 labs (which apparently never saw the light of day) and a quick back-of-the-envelope guess would be around half a million USD of labor. It's way, way more expensive than it sounds if you want it to be legally defensible.

Plus the only people who can write MCM exams would be...MCMs, and at that point, you're talking about fairly expensive labor. Writing tests just doesn't pay that well.