I have made 2 tow bars for jeeps and I fabricated my own bumper with hitch on a 30' class A motor home that was stronger and better than any bumper I have seen since. The bumper was made from 4" x 6" 1/4" wall tube. It was tied back into the frame in several spots on each side. It had 3" solid steel wheels with greaseable pins for when the MH drug bottom going in and out of some driveways.
I have built flat beds for trucks and built trailers. It really depends on your skill level.
Some stuff I have seen that came from an Import factory scares me more than a well built home made project. I have also seen home built stuff that scares me.