You are looking at a long term and large investment of both money and time if you want to do this (which is awesome, anyone who makes their own stuff gets props from me)
We have built a bunch of stuff over the years.
We made an axel out of an actual axel from a ford truck, had a machine shop make the ends and then welded them on.
Farmers walk handles, very simple
Yoke, car deadlift setup (which uses the farmers handles)
I'll try to get some pictures up soon. If you can buy the material you need your best bet is to find a local fabricator and take them pics, they can build it for you and it will be cheaper/better made than most of the stuff that's out there.