I would translate this as "He's three feet tall if you include his hat," although that's not a traditional saying in English. But in reference to someone who is extremely skinny (like a supermodel), we can say "He/she is 100 pounds soaking wet" (that is, including the weight of the wet clothes).
I've heard some of them:Nothing prevents Russians from using expressions, mentioning traditional Russian measures, though: "пуд соли съесть", "косая сажень в плечах", "писать аршинными буквами", "бешеной собаке(корове) семь верст не крюк", "Мал золотник, да дорог", etc. You must have heard some of them.
Мал золотник, да дорог -- lit., "It weighs barely a zolotnik (~4 g), but is expensive/precious" -- thus, "Good things come in small packages"
писать аршинными буквами -- literally, "to write/print in letters one arshin (~70 cm) high"; loosely, it would sound more colloquial in English to say "letters a foot-and-a-half high". But anyway, the real meaning is "to print in a very large font, like the headline of a tabloid newspaper":
бешеной собаке(корове) семь верст не крюк -- usually, крюк means "a hook", but here I think it means "a hook-shaped path", in other words, a "detour". So the whole thing means "Seven versts (~7 km) is not enough of a detour to go around a dog/cow with rabies (бешенство)". I would guess that this is roughly equivalent to the English "I wouldn't touch that with a 10-foot pole"?
I wasn't totally sure about the meaning of the others and had to go Googling.
косая сажень в плечах -- Apparently a sazhen' was roughly equivalent to an English "fathom" (~2 m), so the expression means очень широкоплечный, "very broad-shouldered". But what exactly is a косая сажень (lit., "a slanted sazhen'")? Apparently it was an "approximate fathom" measured from a man's left heel to the fingers of his stretched-out right hand.
And finally:
пуд соли съесть -- This is quite simple to translate: "To completely eat up a pood (~16 kg) of salt." But what the heck does it really mean?? From Googling, I find that it's actually a shortened form of a longer expression: "You don't really know someone until you've lived with him long enough to finish a pood of salt between the two of you" (presumably, this would take several years).