VHF camfacture AG offers a really good milling machines, the hardware is among the most accurate ones for 2x3meters plate and block cutting. They sell more than 1000 machines a year. However, they do not offer a post-processor for Inventor CAM or FUSION CAM, only for Rhinoceros.
I would then request a development of a generic post-processor that can be adjusted for the different range of machines that they have, all of them use the same controller, and the NC-codes are available from the Company.