As far as I know, I don’t think anyone makes a tapered fork. I have been playing around with the idea of a 1.25-tapered cast fork crown.
If you are committing to 100x custom cast fork crowns, it is not much more investment to get a custom bulge butted steerer tapered tube made to go with those crowns. However, a tapered lugged fork might upset the delicate framebuilder multiverse and cause outrage among the purists!
Somewhat related: Battaglin has a set of really cool tapered headtube lugs. I talked to them at MADE, and they said that they have access to casting in Italy, which is what allowed them to make the custom lugset.
Pelago is the only company I’ve seen produce a tapered lugged fork. The Crown isn’t available but it gives you an idea of what it looks like.
Is there a reason you want a tapered Steel fork? ATMO a tapered steel fork is heavier and doesn’t provide any benefit until you get well into MTB territory.
A couple years ago I saw a post where Casey of Mars Cycles took a 1.5" hole saw to a Paris-Brest crown and then brazed the two pieces to a a Paragon tapered steerer. Cool looking, one-off fork.
I have done a few. Here’s the latest one on the lathe getting the crown race cut to dimension.
Before Paint:
I like lugs but prefer straight blades for disc forks (i suppose I do for rim brake forks as well) so, I take a hole saw, cut the steerer miters at an angle that matches the rake I want.