Personally I think the greatest diversity in car design and coachbuilding was pre-war. I've just been re-reading Lawrence Dalton's 'Those Elegant Roll-Royce' which has photos of around 300 pre-war Rolls-Royce cars, from different coachbuilders such as Hooper, Barker, Windovers etc. There are fixed head coupes, drop head coupes, saloons, limousines, sedanca de villes, 3/4 coupes, roadsters, broughams, all-weather tourers, and some with very famous bodywork such as Roi des Belges and Salamanca. Bearing in mind that at any one time these would have been on only 2 types of chassis, the Small and Large HP, I think the variety is incredible. It's one of the main reasons I prefer pre 1960s cars - go to an RREC event and there is always a great variety of cars. Go to an MG event and there are lines of MGBs all the same (and I own an MGC, so I am not knocking MGs or their owners!).