Hey dj,
I'm not sure the cost of the 408 brass but it's based on .505 Gibbs cases that are built up with extra brass in the sidewall just ahead of the web. Bruce Bertram designed and builds cases for this round but his Gibbs cases carry the same design (as it's a good idea even in that caliber) and could just as easily be used for a .338 version....wildcatting is great fun but I hope you have deep pockets, my friend! BJ