I also found that you could use the same CAD program that I learned to design PCB's to draw outlines to cut out on the laser CNC machine at the local maker space. I ended up finding a niche on ebay building open air computer cases. Because of the economics of shipping large items from overseas and the low cost of the materials I was using I was able to under cut the imports on price by like 60% and still make a nice amount of money on a $/ hour basis.
In hind sight the best way to find these kinds of opportunities is not to be looking for them. You really just need to get a really deep understanding of a hobby or industry or market that interests you in some way and once you have that then these sorts of things kind of pop out of the woodwork.