I am assume you mean the ones you have taken the time to whip out and not that you are going into the bender biz.
I believe copying is a form of flattery until you profit from it. That is one of the problems we have with China today. When I bought my JD2 I actually bought from the company owner...he spent a good hour with me and made a special die as well. Super nice guy. He told me how he was building a roll cage years ago using a Hossfeld and could not believe how slow it was. He then came up with the ratchet design and sold the heck out of them.
If I was gonna screw over a company by being too lazy to design my own bender, I would pick some fat cat CEO type not a regular guy that has to come to work everyday and and labor, just like you and me, like Pro-Tools and others have done.
I doubt that is what you plan to do tho.