I've finally (after well over 80 hours) succesfully come up with a plug and play solution for megasquirt and the 22re.
The system is + 1 wire (used to ground 02 sensor heat) and
+1 connector (a vacuum hose).
Literally it swaps in within 30 seconds if the kick panel is out.
Cost is currently $350 - I refer to DIY autotune. I'm not reselling for them, I'm simply passing on their successful implementation of this system. I'm working on an assembly source that will allow me to sell these for $300, but to date, I've spent a *ton* of time on the issue and the boards are have not been built to my satisfaction level. As such, I'm no selling them right now.
The harness itself, I sell for $125.
I can do harness for the 22RTE also for a similar cost.
Sorry, this really shouldn't be a "forsale" post in this forum - it's a notice that this integration has been successful and you can buy fully pre-tuned and pre-configured programmable EFI system for under $500.
I'm happy to show anyone how to do it *for free* or provide advice at no cost. Control fuel and timing, go turbo, change injectors - whatever you want to do. No more factory EFI limitations or having to get an engineering degree to implement megasquirt.

I'm still doing fine tuning...