A solution to NOT drill your track forks and have a normal front brake nonetheless

That's something I'd like to find out more about. They are definitely butted in a way, my own forks for example are (like every 1inch fork of course) 22.2mm inside at the top, and 19 at the bottom.
As I am not at home at the moment I can't measure if thats a soft transition up to a certain point, or if there's a step involved.

The last couple of steerer tubes I've inspected that closely have had a reasonably smooth transition, maybe 5mm or so. That said, they were both Claud Butler forks from the 50s - although they weren't the same model and had different crowns, they'd probably be pretty similar.

Either way, I suppose the stem could have two expanders to keep it snug no matter what the butting is like, then top it with your security device of choice.