My brother has a trailer for his Honda VFR800. He took a Harbor Freight 3x5 utility trailer, narrowed it some, and I built an elaborate hitch substructure that picks up on the seat and motor mounts. We extended the tongue a bit, and used a 5/16" female rod end on the trailer and a pair of tabs and a pip pin on the bike; just stick the rod end between the tabs and drop the pin end. The rod end rotates on the threads on the "stinger" on the tongue when the bike leans. We figured there'd be years and years of service life before the threads got worn enough to worry about, and it has a lot more range than a typical ball hitch - the motorcycle can fall completely over, or turn more than 90 degrees, without binding the rod end.
I was dubious about the whole thing, but even though the empty trailer weighs 150-odd pounds it tows like a dream. You can't see it in the mirrors, and you literally forget it's back there. All the concerns we had about weird trailer effects on a single-track vehicle turned out to be unwarranted.
It costs me $20 in gas every time I go to Kenney's now. I'm going to build a trailer for my Bandit 1200. I'm going to use an 8" tire and axle setup instead of the 12" that Kevin is using, mostly because I can get the parts for free. The tires aren't that much smaller; the rims are smaller, but the sidewalls are taller. I'm also considering welding the axle to the frame and dispensing with the springs. Kevin's trailer is rated for 1600 pounds, and he can jump up and down on it and move the suspension maybe half an inch.
Kevin suggested building an asymmetrical hitch - bolt a bracket to the right side of the swingarm, opposite the chain, and offset the tongue. The coupling rod end would be three or four inches off the bike centerline, which would theoretically require some steering correction... but for occasional moderate trips it shouldn't make any difference. I'm going to weld the chassis out of 14 gauge 1" square tubing, and I have some expanded wire to make a floor. Just 2x3 feet or so; all I need to carry is a block or a pair of heads or something along that line, payload in the 150 pound range. There's no reason the trailer should weigh more than 40 pounds or so; I could pick it up and carry it if I wanted.
Kevin's hitch is mounted to the chassis, and his trailer wheels are approximately centered under the trailer deck. Tongue weight on the trailer shows up as sprung weight. He's only using 10 pounds or so of tongue weight, which seems to work okay.
The hitch I'm planning for the Bandit, being mounted to the swingarm would carry all the weight as unsprung. This would theoretically make the ride harsher, but I doubt it would make any difference. I'm also planning on mounting the wheels at the extreme rear of the trailer, so I'd wind up with the load on the bike tire as a fixed proportion of the load on the trailer tires. A guesstimate of the trailer weight and cargo would be 50-75 pounds at the tongue, which is a lot less than the weight of a passenger.
I figure, over the course of six months, I could save enough on gas to pay for the insurance on the bike. The trailer plate is $45, but in Arkansas that's a one-time fee, and the plate is good forever. Property tax would be $5 or so per year, I think. With construction costs, I'd break even in about a year, just figuring the usual trips to Benton. There's a lot of running around I do where I have to take the Malibu; I have packages delivered to my Dad's address; for example, or mailing packages at the Post Office, or making the occasional run for groceries.
I combine as many trips as I can, but the Bandit still gets twice the mileage of the Malibu.