Finally decided to mount the extinguisher on the side of my cargo area. Another thought was on the back of my rear seat, but this way all I have to do is pop the top if I need it and reach in to grab it. Got a nice stainless steel (at least the guy was told it was stainless) mount for it so I don't have to worry about any bimetallic corrosion where it's bolted on (there's a vertical support that it's mounted to through the trim panel). It's not as easy-access as the A pillar, but given the height my seats sit at, it's too easy for people close to my height to crack their forehead into it when getting in.
