The raw tamahagane that is used to form a billet before folding sells for over $100 per pound. You add a lot of effort to fold the steel and forge weld the high, low, and medium carbon content billets together to make the general blade shape which would add substantial more cost. If you plan on machining the final shape you have to be able to provide all of the final dimensions so the smith can make sure you have hardenable steel at the edge. That makes it a custom job. If you want one of the best smiths be aware that they often make over $20,000 on a single blade and your project would be hardly less effort for them. Yoshondo Yoshihara is one of the best but I doubt he would take the job. If he does agree to it there is a two year waiting list for blades he has already been commissioned to make.