Why not a Boulevard? An S40 is pretty tiny (formerly known as the LS650 / Savage). :)
Seriously, though... I had the teeny tiny 4x4ish Harbor Freight trailer, primarily intended as an autocross trailer to tow behind Miata #1. That said, when I got a bike, I thought it would be handy to be able to tow it around. So I bought a "motorcycle rail," also from Harbor Freight. It was probably intended for a 4x8 trailer, but it worked with minor modification on my 4x4. The rail just stick forward onto the tongue a bit, and stuck out the back. Basically, it's a rail that the tires sit in, with a bit angled up at the front to hold the front wheel securely. At the back there's a small ramp that attaches and detaches.
Small problem - I had a 1980 Suzuki GS550E. I don't know what the wheelbase was, but it was long enough that when the bike was loaded, I didn't have enough room between the rail and the back tire to pull the ramp out. I had to MacGyver a short extension in the middle of the rail to stick the rear portion back a few more inches so I could get the ramp out.
An Escort could tow it fine. My Miata and my FWD Civic wagon had no trouble with the weight (about 500lbs, plus the trailer itself).
The trailer itself bolted together just fine. Welding not required. However, the wiring for the lights took a lot of extra work. The paint they use is a great insulator, and turned the wiring and grounding into a nightmare. Scrape off bits of paint where the pieces of the frame meet so they'll touch and maintain a decent ground. MUCH easier to do this during assembly.
