Just to complete the story and maybe provide some help for later readers, I called eurotech in vancouver (
http://www.eurotechservices.com/) and ordered a set of three 300mm blades for my MM CU300 at a cost of $85.
Apparently they get the stuff in coils. Gulp. Imagine a coil of tersa blade coming undone, like a giant (120m I was told) ultra-sharp bandsaw blade. Best hope you're not in the same county when it hapens.