As a suggestion, you should make decals next for full outfits.
Yeah, except I'm not sure how I'd go about making Senketsu and Junketsu; I mean, Ryuko's navel is my main concern, as I'm not sure how I'd be able to implement it in one of two ways -- making the uniform itself transparent, or vice versa, leaving the navel transparent.
I'm sure the second option would look ugly, though.