Yep, electrical modifications can be fruitful, especially in a hybrid. I finally got the IMA inhibit switch working almost exactly the way I wanted.
In stock form, the car is too eager to use electric assist. I found it used assist almost every time I left a red light. Drawing energy out of the battery, then putting it back in with the gas engine, is generally less efficient that just using the gas engine alone. When I'm ecodriving, I want to use only as much assist as I can pay back with regenerative braking (and I brake as little as possible).
The solution is an IMA inhibit switch. When the ECU thinks you've got your foot on the clutch, it won't use assist or regen. The simplest IMA inhibit switch is just a toggle switch that, when closed, electrically connects the two wires going to the clutch pedal switch.
That works fine, but you have to switch it off manually for regenerative braking. This is a distraction, and it results in missed regen opportunities. I added a relay so that when the brake lights are on, the IMA inhibit switch is ignored.
The ECU delivers +5V to the clutch switch on the red wire. Splice into that, and run a wire over to the correct pin of the relay. Likewise, run a wire from the green/yellow wire from the brake pedal switch to the coil of the relay. The electrical resistance of the relay circuit needs to be "much larger" than that of your brake light bulbs. >50 Ohm is fine. If your relay has less, add a ~500 Ohm resistor.
I installed this mod in the driver's footwell, using inline splices to tap into the brake lights and the clutch switch at the pedals.
When I get around to constructing MIMA_L, I might move all my electrical mods to a breadboard near the passenger footwell. Between MIMA_L, the engine kill switch, IMA inhibit, and IACV inhibit, I'll need to cut 8 wires and tap into 7 others. This is best done right where the wires enter the ECU.