The 8mm/338 win mag is a wildcat but an easyone and it is not a new one ether. Brass is very easy to make, ether open the neck on a 7mm rem or neck down a 338. The dies can be order pretty easy. 8x68s is a factory load but not all that common.
The whole point is to build something that both works and is a little differant.
Heck the easiest wildcat of them all is none other than a 8mm/06 which would be a 8mmX63.