Someone who towers over her enemies. Someone who could go in one-to-one combat with any of the League's strongest male champions, matching them in strength and endurance. Someone who would scream bloody murder about turning your entrails into a necklace, but happy to crack jokes once her rage is settled; a pleasant medium between
and
. Essentially, a character who loves to fight but not to the point of obsession.
As for body type, the best I can imagine is: http://img3.wikia.nocookie.net/__cb20080813052235/diablo/images/c/cd/Fem_barbarian.jpg
Nothing overtly sexualized (butt, breasts, and the like are at least reasonable), granted she is still wearing little more than a bikini, which is a bit silly.
As you can imagine, I do not think a character of this type would fit anywhere besides Freljord or Noxus. Maybe Bilgewater. Demacia is too polished, and they already have Shyvana, who has an absurd hip/waist ratio. I mean, holy shit, who thought that was a good idea? Ionia could be a reasonable fit, but I have difficulty seeing a fierce warrior who focuses on brute strength to originate from there. Shurima just would not be capable of supporting someone of that size, even with Azir uplifting it to a more livable country.
Also, off-topic, but I would like a male champion who is thin and effeminate, but not gay. A character that indulges in life's finer pleasures like
, but sensual and utterly cruel like
.