McCallum, I find your listing of axle manufacturers interesting. I don't know about the others, but I do know just a little about Dexter. In 1990, I had a 5th wheel travel trailer with an entire suspension system that was too light, so I visited the Dexter factory one morning, sat down with one of their engineers, and we custom designed a complete system; first selected the axle tubes, the type and size of hubs and bearings, type and size of brakes, springs, wheels, etc. When we finished I asked, "How long will it take you to make them." He looked at his watch (getting close to noon) and said, "Well, I couldn't have them ready for you before tomorrow afternoon." Needless to say, I was amazed that they would be ready that quick, but he said, "We're making 1500 a day here." And they were ready as promised, and a lot cheaper than I expected, too.
Bird