I have 40 to 50 models that I have collected by hook or crook over the last 40 years. Don't have the nice display shelves like yours yet, but I'm working on it. I've bought some off ebay, some from DHS or Buffalo Road Imports and some from other on-line sites. I currently have several kits to put together when I've nothing better to do, one is a rare plastic Michigan scraper that I bought from some guy in Switzerland. I have two or three of the AMC D8H kits, one is complete.
Don't buy so much off ebay these days as some of those guys jump in way early and run the price way over what it ought to be. Sometimes buying the same item direct from other on-line sellers is far cheaper. DHS has a nice page devoted to buyers and sellers of models, there are some good bargains there -- sometimes.