With you now!
A tow hitch idea is good, a couple of points to bear in mind regading a tow hitch design.
You can have a flat or boxed bar made up to any shape you want to fit a tow hitch, when you fit the hitch to the tow ball, don't forget that not only will it swivel from left to right with ease but it will also swivel from top to bottom, this may cause you a few problems, like when you pull your hose it will tend to pull the hitch up if the hose is higher than the tow ball, I see a trip hazzard but its something that can be worked on to get it right.