That could definitely work! I will have to cross the cable over to the other side, and I believe I saw people do that at the rear seat, but is it much hassle?
Any idea if the firewall at the pedals is single walled and might be easier to attach the power cable to the secondary battery terminal on the driver side, drop down the engine bay to the pedal area, and pass through there. That way it's all on one side and the cable is on the side that the amp will be.
I haven't gotten around to removing all the plastic covers near the driver pedals to see if there might also be some grommets I can pop the wire through as well.