I looked into this once before, but decided to keep my Girard for the time being.
I didn't keep my notes from that research, but the lynch pin is the exterior opening and the internal cavity needed for it. My dealership said that nothing would fit, but I don't feel that is 100% true.
Carl & Dawn
2015 Greyhawk 31FS
2015 Ford Transit Connect (our TOAD on a DEMCO Dolly)
DW, DSx2, DDx2 Catx2 Dog
Tampa Bay Area of FL