This problem is now fixed.
My original assessment was incorrect. The problem was power. If I was running the computer on Battery, then the VMware guests all crashed with various strange errors on startup. If the host is plugged into mains power, then everything works as it should.
Clearly, on battery, my computer is shutting down some processor capabilities. Only on full power is everything there.
For others that might have the same problem:
Acer Iconia W700 Core i5, 4GB RAM, 128SSD. Factory power settings.