I did a bit of riding for Scooter-Media up in Seattle last summer and I thought the trailers were pretty sweet as well. They sort of build them up themselves from a basic axle/wheel set and fiberglass pan. The cool part is the hitch - it bolts on with the engine cover bolts (along with a couple support points) and on the trailer is a regular ball tongue that gets a custom rotating joint added (so it {the tongue} can roll from side to side about 30 degrees or so). There’s also a tiny european trailer called a Pav that would probably be more practical - someone up here in Portland imports them and has them on craigslist from time to time for about a grand. They look sort of like a unigo and have just one wheel.
If you have any questions you can reach me through the email link on trycheckthis.com (glasses at the bottom of the page).