The million mint nodes would have to run a decentralized program of their own, a many-multi-sig wallet application.

Let's say a group of 192 peers coordinate to establish a mint. Some mechanism is used to be somewhat sure these are not 2 with 190 copies of the bad actor, some minimum PoW, WoT, anonymized reputation management, or combination. A 2/3 majority is needed to post on-chain, and a smaller number is needed to mint e-cash. The point is to distribute trust as wide as possible.