Just chiming in here...to the OP...it's NOT simply " I have a hard time seeing that a rolling vehicle would subject the hitch and frame to huge acceleration forces." that will bite you in the rear....
It's the dolt that cuts you off so you have to slam on the brakes....it's the blowout on the dolly that will throw you into a spin..maybe some bad weather or high winds....it's the myriad of 'other' unknown factors that might be thrown at you in your journey that will cause you to regret your decision to over tow....just sayin.....Dennis