I have used 1" threaded forks, then 1 1/8" forks in a MTB frame. I got the frame with no forks. So just fitted 1" forks with some headset bits I had.

I think some BMXs had 1" threaded steerers but had the wider diameter headstock. So maybe a BMX headset would suit. So you can get a 1"fork, and better looking stems.