I don't know if this counts as a clothing transformation but it's a real good one.
So I don't know if most of you know it or not, but there's an anime called Kill la Kill that's very crazy with action scenes and complete randomness. But before the battles, the main characters turn their clothes, mostly school uniforms, into combat armor in weird and half naked ways. All of them were very detailed and made them look extremely tough. Sure there are guys turning their clothing into battle armor too, but I think the women changes are a whole lot better. That anime is on Netflix if anyone is interested, but if you want to see the clothes changes, here's the link...
Kill la Kill: All Transformations