I do this sort of thing, but more on the woodworking side of things. I'd look into your local maker spaces. They are filled with one to three person companies d

I do this sort of thing, but more on the woodworking side of things. I'd look into your local maker spaces. They are filled with one to three person companies doing lots of projects just like this. I'd recommend have prototypes made using a laser cutter and then final parts machined later. Another option is to just learn to do it your self. Many of the maker spaces will have have classes on metalworking, welding, aluminum cutting, CNCs, laser cutters. I also TA as a 2.5 day weekend workshop on the central coast that will teach you to woodworking and welding. Let me know if you have any other questions.