I've built them for other types of machines and they aren't bad to build. Not a complicated item to build. Not knowing if you weld or what you have in tooling makes difficult to give you ideas but I would suggest looking at a few designs on other tractors and using some of there ideas. You can build these things as simple or as complicated as you like.
I have the stock one, just remember is is going to have to tilt forward, or be built far enough forward for the hood to open. The stock one pivots forward.