I wonder if this will have an implication for running Linux on Surfaces, I hope it does because they're a very neat (and affordable - inb4 Asus Transformer) piece of hardware but I have little use for another Windows machine.
I agree. After playing with one of the $500 Surfaces, I thought, "Man I would buy this in a heartbeat if I could wipe it and install Ubuntu".
The Surface doesn't carry the third-party signing key, so in the absence of a flaw in the firmware implementation you're not going to be able to run anything other than Windows.
That's great info, thanks. Disappointing but gratefully received.