Part of the difficulty is Ellie is rarely standing next to a not-Ellie-sized person. if there was a comparison for scale, peopel would realize her head *IS* normal, that the rest of her is JUST. THAT. HYOOJ.
One thing I am mildly curious about is if there's ever going to be a part 2 of the Panther Panties storyline with this character. Part 1 came out in 2009, ended with a "To Be Continued" and, as far as I know, that was it. I wanna know if Elli and her magic panties had any more adventures!
Guys, I think her head is small to make her body look proportionately larger. If her head was larger, she would probably look kind of top-heavy, like a bowling pin. It's a common feature of muscular characters; you may also notice that Mr. Incredible from "The Incredibles" has a proportionately smaller head than the other characters to better communicate his large physique: [link]
Of course he has small legs for a similar reason, but Elli needs big and powerful legs for what she does.