With pulling a boat behind my 5er, I searched out a solution for a bike rack that did not take up my hitch. I found a couple of really bad King Pin bike racks and then I found this one. It is very solid and after my first trip, it proved to be a great choice.
http://www.toppoprails.com/
I got the two bike version with the extension for the short bed.
Does it have a mechanism for removing it when you are not carrying bikes? (short ofunbolting itfrom the pinbox) I have toyed with the idea of fabricating a tray type bike rack that would mount to the frame on the back of my 5er but just can't "pull the trigger" on it.