Many years ago, model kit manufacturers did do more in the way of kits of the old cars; about a year and a half ago, I finished an old MPC kit of a 1932 Chrysler Imperial. I even did a bit of backdating on the hood and did some engine and interior detailing. I also have an ancient Johan kit of a 1934 Mercedes Roadster; sadly I had to rob this kit of the chrome wire wheels and a couple of other parts to build the Chrysler--the Chrysler kit did NOT have the chrome-plated wheels I wanted!
Your best bet: bring some cash and look for these old kits at kit exhibitions and model contests (are you coming to Phoenix for the IPMS contest?). Also consider looking for them at collectibles shows unrelated to model shows: I found both the MPC Chrysler Imperial AND the Johan Mercedes Roadster at an insulator and bottle show, of all places!