I just posted a similar thought in response to Michael's note, above.
A suggestion for folks in the US might be to leverage the soaring
community in other countries to do their research there. Every time
I've been at a glider operation in Germany, I've seen tow hitches that
blow the doors off of anything you can get in the States mounted on
cars that I've been told "cannot possibly tow a glider trailer."
Granted, many of the towing distances are shorter, but the Autobahn and
the Alps equal anything we have here in terms of testing towing
capability...

On a humorous note, the paid placement ad that's showing up right over
here -- is from Dalan Hitches, maker of the aftermarket hitch for
my Passat that I so roundly criticized in the prior posting.