The old Campy Pista headsets have a low stack height, but these days cost more than a crashed Trek frame is worth

There is a version of the Gran Sport road headset that uses the smaller bearings and has the same low height, but even those are tough to find and expensive.

Check some of the current 1" track headsets that are available. I think the Business Cycles website has specs on stuff like this, or at least could tell you if you email them.

I think the late 90's Campy Record road sets were pretty low as well?