Lots of people have made home-made motor mounts. Even Rick made one for one of our boats. It was real simple, just about a 40-inch length of 1"x6" teak with a built-up place in the back to screw the 2-hp motor to. It was designed to be tied down to the center tramp lacing and to the aft beam. We never used it because we couldn't get the motor to work. (Internal combustion engines belong to the same union as bilge pumps -- none of them work when you most need them.)
I am told that we have an outboard motor mount available through our on-line store, but it is not listed there yet. You have to e-mail
rick@catsailor.com and ask about it.
However, I think it is a lot more fun, and cheaper, to figure out how to make one yourself.