Euro-Asia Imports has a headset made under the "Star" brand that was VERY short compared to the standard 35-40mm stack heights of the "standard" Campy-Shimeeno road models. Not absolutely sure if they still make a threaded version, but I think they did.
Not on-topic, but this might do the trick to SAVE an on-topic frame with a too-short fork.
As a last resort I have shaved a coupla millimeters off of the headtube and fork crown race seat. Not what I would have wanted to do at all, but sometimes you have to do what you have to do in order to get someone's franken-bike together.
San Francisco, CA