As far as I know, these wheels aren't make from a multi-axis mill. From the
Truespoke website, where the picture you linked is from, it seems as if these particular wheels are put together by hand. The spokes, rim, and hub would all be separate parts. Regardless, these wheels are excellent craftsmanship and it can certainly be a good CAD project to create a design inspired off of these.
I am curious about the cost evaluation on the part. When you say that the 8 spoke design is significantly cheaper, did you get somebody to do an evaluation, or is this your own estimate?