Not sure if it would fit with your bumper but I cut and flipped my receiver upside down. Can't say if will work with your bumper since I removed my bumper beforehand. However, it looks like that may work.
Here's a link to get an idea of what I mean and whether it looks like it will work for you. It brought the receiver up to between the frame rails.
http://www.toyota-4runner.org/3rd-gen-t4rs/75010-flipped-draw-tite-rear-bumper-platform.html