Me personally, I just like feminine looking cross-dressers. It sparks more controversy when the guy can be mistaken for a girl, as opposed to a clear joke of a man wearing female clothing. As for nationality, I'm going to say Japanese. With a visual kei type image, since the style itself promotes cross-dressing.
I don't mind feminine but I just think it's generic if they follow the same trend of giving them a petite body and a short height.
As for nationalities, I prefer something exotic. Japanese comprises like half of the roster's characters. It feels like nothing is new. My ideal crossdressing fighter is a freckly Irish redhead. There's generally a lack of gingers in the roster for both genders.
Well, maybe French then. I know Visual Kei / Lolita style is actually big over there. So I wouldn't be surprised if they threw a cross-dressing French guy with the visual/oshare kei image. Kinda like this guy ( though Hizaki is Japanese. But still. ) http://userserve-ak.last.fm/serve/500/12650341/HIZAKI%2B%2BCurse%2Bof%2Bvirgo3.png
I do want a cross-dresser with a Marie Antoinette's powdered wig hairstyle + Victorian dress default costume. I guess it's high time France gets a male representative. That outfit on the crossdresser would match Helena's 2U C3 since Helena is in trousers with tights.