For a tinkerer like me, CAN bus is the work of the devil, as Captain Anchovy would say. I don't see any need why, for example, the windscreen demister flap controls need to interconnect with the engine management system. It reminds me of Jimmy's Doohan's line in ST3 : "The more they overthink the plumbing, the easier it is to plug up the drain...." But I don't really know anything about CAN bus, so YMMV. The need for a CEM plus an ECU in the system does explain why used Denso ECUs are going for about $70 USD on eBay.
Anyway, Maxx ECUs advised me they do the MaxxECU PRO Premium kit for roughly $3,800 AUD, which could control both the B8444S, and either an AW30-43LE or a 4L60E sitting behind it.
However, they don't have a B8444S harness available off the shelf. The Premium package comes with a loom, which one has to make up oneself. Sourcing new connectors could be a chore, but that isn't the biggest problem.
Since I am hardly a tuning mastermind, not even in my dreams, I will need to find somebody around here who is either familiar with this system, or is at least willing to tackle it.
An activated M190 with auto trans license is around $6,300 AUD RRP, plus harness. There is a local MoTec dealer over near here, too, which makes support and tuning less problematic.
Is saving a couple of grand on just the ECU really a saving, I wonder. What may be saved in component purchase will likely soon be eaten by the local tuner's need to learn the system, if they are even willing to tackle it.