How about this idea that I just thought up:
Place ads in the major organ & choir magazines (AGO Magazine, The Diapason Magazine etc.) inviting builders who may be interested in building you a new organ to contact you...a bit like a tendering process, though you don't necessarily go for the cheapest.
Invite the builders around one at a time, and tell them your budget to see what they might come up with.
Has anyone ever tried this kind of method, rather than going through a large directory of organ builders one by one?
Currently own:
ALLEN TC-3S (#42904 - 3rd Feb 1971) with Sequential Capture System
Speakers:
x1 Model 100 Gyro Cabinet
x1 Model 105 Cabinet
x3 Model 108 Cabinet