Thanks for the update. Your prices are already pretty much on a par with the only other coating blades widely available, those used for testing paint.
Still out of my range though
It was used quite extensively at my previous place of work.
I think you would probably be looking at a multi-pass operation on high grade Stainless of the thickness you are dealing with, but even so, I think it would be possible.
There is another alternative, as sometimes used by moulding tool makers, which involves bolting flat sections together with precision dowels for alignment.
I think that if done properly, this could also work quite well.
Have you ever considered a "budget option" of a milled plastic body with a stainless doctor blade? - particularly in the smaller sizes.
Delrin would probably work reasonably well, as it machines and finishes well, and is dimentionally stable.
I think if you could produce a cheaper option like this, emulsion coating would come within the range of more people.