Hey, I have been thinking of some base skins for Black Cat after reading Cable's message in the request thread (plus, I like Black Cat myself, too!).

I think Medusa is a great choice for Black Cat. The only draw back is her oddly shaped chest. The cleavage of the model (not the texture) will look nicer if you use female skeletons. This is probably because of how the female skeletons bend at the waist. This is why I used a female skeleton for She-Hulk.
You can also try Black Widow and Ultimate Storm, too. They have different hair styles and and other stuff, too. If I have the time to make my versions of Black Cat skins for MUA, I will definitely use these three models. Spider-Woman would be the best candidate if I could hide the glider wings...

EDIT: Textures tend to stretch unevenly near the middle (all the way from neck to the private region) of the female models. So, try not to deviate from the original shades that much... The bigger isn't always better...