Back in 2002 I sent the kind folks at Cobra a note explaining that for
something like $30 in parts they could make any trailer headed for the
US plug and play.

Simply plug in an adapter to convert "euro" to the typical "flat four"
connector and flip a single switch at the back of the trailer. It only
would take 60 seconds at the port for the new owner to be driving away
and the lights would work. I suggested they just add $200 to each
trailer as "standard" and no one would ever bring up this subject again.