I think Psylocke sits right up there as far as having a convoluted (confusing) backstory that's covered up by how cool the character is.
With a little free time recently, I had some time and energy to paint this design up. The original design was done a few years ago for a class demo that walked students through a step by step process from sketch to final. Since it was a live demo, I only got as far as doing a quick colour pass on the design.
The main idea for the design was a 'civilian' or front facing outfit for her that retained the feel of her costume without it being just being a swimsuit. While her comic outfit had very 90's cool/sexy factor to it, it was probably something you wouldn't be wearing in a school setting. So this was a design that kept some of that cool/sexy feel, but more slick and contemporary, and most importantly - won't get you fired from a school.