Any chance you could use an extension handle like is common on luggage as part of the trailer tongue? Unfortunately that might require a straight-pull hookup, perhaps like the
Burley Travoy, or perhaps a rack with a center trailer hitch.
My Swiss Army bag has a bit of an odd rounded shape, but the single pole might be strong enough to use as a trailer tongue. It is, of course, a soft backpack convertible suitcase.
