Claymores are not generally the full height of a man, I don't think.
Right, a Claymore is usually around 4.5 feet. The actual blade part something like 3feet of that, with the Handle, Pommel, Hilt and foregripping area taking up a good 2 feet.
Anyway, some inbetween weapons like longswords should (as they do in reality) have an option to use them 2 handed for faster/stronger attacks.
Hand-and-a-half (Bastard) Sword.
It's probably too much to expect, but if you equip one of those types of swords, with nothing in the offhand, they could (Either through perk or naturally) occupy both hand slots, for an increase in damage.