In australia, alot of the headertrailers are towed in nothing more than a heavy duty towball. If you want to make a trailer, just go for it! build the dolly yourself, and put a turntable on top of it! Thats how many trailers are made in Australia. Homemade!
We had our home made hitches to the left side, too. For once you have the chance to see the header in at least one of the mirrors - the left one. Second, when you have to drive the combine into the ditch to make room for other traffic, the header may stay on the road and not tip over and into the ditch.
No traffic problem at all. This is what makes this set up a breeze to haul down the road. As ralf pointed out, when you meet up with oncoming traffic and need to move halfway to the side, the header/trailer still stays on the road while letting traffic pass. Also makes easy turning into the right side approaches into the fields. Left side turn approaches into fields may need extra attention depending on how wide the road and approach is. The tighther it is, the more you need to move over to the right side of the road in order to make the left turn into the approach. So far so good. Like I said, well worth the investment. Saves time, less manpower to move from field to field.