I think Darwin Cooke's resign of Selena's costume would work nicely in Nolan's films, there's nothing outlandish or strikingly silly about it. It's a form fitting body suit essentially with goggles. Make it armored if you want to for maximum protection.
I rather think a cat-burglar would want to keep their kit as light and unencumbering as possible. Armour would only slow her down and actually increase her chances of getting hit. She's be better off relying on stealth and speed to present no target at all. So an all black, or charcoal grey catsuit (jet black actually stands out in shadows, believe it or not) with a dull (NOT shiny) finish would probably be the best choice. It'd still need to be tough of course, just not *that* tough. Good enough to guard against cuts and scrapes but certainly nothing that could stop a bullet.
As for as design for Harley's outfit, I think something along these lines
would work quite well.