If you really wanted a small, but exquisite collection of Hamilton models centered around a single theme you could focus your attention on several potential options. One might be to collect all the CLDs, there are 19 different models, but good luck locating a Tildon.
Another option would be to obtain all of the Lord Lancaster models that feature diamonds in one form or another. There are 21 models to attempt to find and some will cost you plenty.
A third option would be to focus solely on watches cased in 18K gold. There are only 13 cataloged models with 18K cases. One of them is the Barbizon from 1957, which I used to call the Unicorn, as everyone had heard of it but no one had ever seen one - until they did. There's only one known to exist. Priced at $2,200 in 1957, you can imagine why...that would be $23,500 in today's dollars!
One of the 18K models you could try to find is the 1959 the Thin-o-matic T-101. It was mentioned in the 1959 catalog and looked identical to the T-201, which was cased in 14K gold for the hoi polloi. However, the T-201 was offered with a solid 14K bracelet, which would have been pretty special.