The big breakthroughs in SLR design came in 1959. In 1958 the Contarex could arguably lay claim to the "best SLR" title. Its competition at the time would have basically been the Exakta. The Exakta despite being an old design by this point was the more flexible system and better suited to laboratory and scientific uses.
I think the Contarex Special is actually a very attractive camera too: http://www.pacificrimcamera.com/pp/z...ex/special.htm
The Contarex Super and Electronic also have their own interesting aesthetic appeal.