I love the Panzershop WWI kits. They are a bit of work to assemble but they are much better than Emhar. Here are two pieces I have started but yet to finish.
The photographs show very well the derivation of the first model. This was noted some time ago on this forum. It does seem that there are also some more original products.
Thanks for your comment about my work. Of course your Mark IV is beyond amazing! This could be the best Mark IV I have seen - and the fact that it's based on Emhar is even more fantastic. Look forward to seeing more of your work.