Sort of worked...
Aaron and I went for a squirt today, he looked at the gauges while I drove. We found my ecu definitely opens the throttle 100% at launch, but only if the brake was off for a second or two beforehand.
I looked at the ECU diagram and found the brake pedal input wire, not knowing if it would put the car in limp mode or if the brake lights would work, I snipped the wire and backed the car out.
The brake lights worked, and now I had 100% throttle at stall. A drive told me the abs still operated and the takeoff was much better, with the car hitting the 4000 rpm stall limit off the line with little effort.
I will let you know how the car drives over the next few days and if there are any side effects but for now it looks like Pipster pointed us toward the holy grail.