Correct, FJR. You need DOT numbers if your towing over 10,000lb trailer for commercial use. I have two F350's. The dump is 12,500lb GVW, the single wheel is 9900lb GVW (the single wheel is a personal vehicle, only plan to tow in emergencies). My grapple trailer is 15,000lb GVW (10,000lb usable weight). No matter what in the end I need a CDL, and am willing to get it as it will open other doors in the slow times.
Thanks for the suggestions above, I guess I really need to talk to a state official about it. There aren't many nice rear mount trucks out there, and finding one under CDL even more rare. "My" truck is a CDL truck, so I have to look into it further.