The reason the magnum looks like the deere (8000) is because one of the design team went to work for case ( as it was back then) You can copy all you like but noting is as good as the real thing !!!!!!!!!
A John Deere man should not talk about one manufacturer copying another. looks to me like Deere does a lot of copying themselves, like the all of the T series tractors and maybe the STS combine to site a couple of recent ones. You can also bet that all the manufacturers know exactly what the other guy is making they are usually one the first to get a new model and tear it apart piece by piece to see what is good and what is bad.
apparently on the new jd combines they are having problems with their stone traps so at one ag show that a TR was at there were a couple of jd engineers looking at every detail of the stone trap so they could copy it.