I seem to remember, back in the '60's, that armour was done mainly in 1/32nd scale, though not many were available, just as aircraft kits in that scale were appearing. There was debate about which scale should be used as a standard, but Tamiya, having already just launched a huge range in 1/35th, won the day. There used to be quite a few 1/48th armour/vehicle kits then, which went nicely with the aircraft, long before the current re-appearance of this scale in armour kits. Funny - Tamiya again!