Unless you can find a shop or individual that has a screw machine lathe set up to do such work I think that you will find the quote to be very expensive to have them made up. To set the lathe up for one size, they would have to run a considerable amount to justify cost. Then you go to another size and the same happens. I don't know what the minimum of each size would be and naturally the more made the cheaper per piece. Also, in the higher grades who is going to engrave the heads, and now you are faced with a few differences between sizes in the Regular frame and FW frame plus two more screws for the FW. I believe an individual would be cheaper because he is his own time.
One big issue that I almost forgot and is the really important item. In order to orientate the screws showing they either have to be made longer in the head size with a slot and tightened and then marked as to orientation, again cut to size and then slotted again. So you can see where this goes. Some might be happy with no orientation, but I wouldn't even though I have some that are not.