You other option is to "flip the axles". This is done on lots of trailers behind "tall trucks" (4 wheel drive), or where shoving the pin box further up is not an option.
I had it done on my fifth, pin box could not be pushed any higher and besides it would have brought the fifth too close to the truck.
What is involved with that is changing the axle suspension on the fifth from under slung (axle tube on top of the springs) to over slung (axle tube on top of the springs). Depending on your axles it raises the fifth from 3-4 inches. Any competent suspension shop should be able to do it, not too costly.