If you have a steel working shop nearby, I might suggest contacting them about fabrication. I've done that a few times and most everything they make for me is from scrap pieces - last mounts made, they charged me $20 (I gave them $40).
If you want to go that route (or attempt it), have design specs ready for them since most of the time, they will charge significantly more if they have to do the designing also. Not all shops have the resources to help there but I've found that those that do will at least attempt to work with you, I've yet to have a machine shop tell me to "get lost" when inquiring about custom parts.