I've taken a gooseneck and made a bumper hitch. I also made it to where you can change it from bumper to gooseneck. This was on a steel Myco trailer. I had some plates made at the welding/ fabrication shop, bolted, and welded them to the trailer and the removable necks. The necks themselves are bolted together.
The gooseneck pulls nice. I also saw this done on a big cat so the onwer could make the boat and trailer fit into his garage.