On a sad note, many fighting girls are completely ignored by hentai developers.
For mugen you can find street fighter characters (chun-li, sakura...) or KOF characters. But there's no 3D fighting girls.
It's too bad, I think I would like a 3D fighting game (like Battle raper) with girls from actual 3D games (or parodying them) like Sophitia from Soul Calibur, Nina Williams, Asuka Kazama or Christie Monteiro.
With clothes destruction!