Karmann Ghia, VW Beetle, Fiat 500/695, Citroen 2CV, Jaguar Mk2 all come to mind immediately as Tamiya kits that would look really good with proper weathering. As would all of the rally cars, of course. The Alpine A110 would look great a little beaten up as well.
Tamiya has a big back catalog. If I have any complaint it's that they underutilize it and don't rerelease their greatest hits enough.