A List of ALL sailboats made with layouts?
I would look for a really good broker who would be willing and able to look for boats you are interested in and recommend similar ones you may not know about.
I think one reason boats are listed by their designers is that boatyards tend to come and go. Two examples are the Valiant 40 by Perry which was built at the Uniflite factory in Arlington Washington for awhile and is now built in Texas, and The Gulf 32 by Garden which was built by Gulf Marine in the 60''s and later built by Capital in the 80''s and 90''s.
Another thing is that hardware the builder uses tends to change literally from boat to boat in some yards because of availabilty or price or some other reasons.
I looked on Yachtworld and ony saw one Siai 52 listed and 2 Creekmore 46''s. While it is probably the best internet site for boats for sale it doesn''t help much with any of the questions you had about specs and hardware.