I'll pull the harness out one more time and look at splices over by the DRAC module and steering column, resistance check on the speed sensor pair look ok, not melted together, broken or going to ground as far as I can tell.
It seems like splicing in grounds to the ECU might have done the trick, I'll know more when I get it back together and see if I can actually drive it anywhere. :-)
[circuit grounds cause all kinds of weird symptoms when voltage gets back through the circuits] < that's the part that worries me, I don't know why or where it failed exactly, but it seems like that's what I'm up against on this one.
Thanks for fielding my question here Jeff, I'll post back when I know more...