Well, it does strike one as a bit weird, but then again, if you are contemplating it, you know your wife. She must be a "go with the flow type." I envy you.
My first reaction when I saw the title of this thread was "wrong country." I know you can find such things in Japan (usually the masseuse is a man, however). But then again, it's true you can find a lot of women in this town who would do it for the right price. I'd think you have to pound the pavement and interview them yourself as it's not something that has probably come up in conversation with most hobbyists.
Off the top of my head, I'd turn to the Koreans over the Chinese, who are more provincial (and they are cleaner, too, which your wife is sure to appreciate).
Good luck and be sure to let us know how it turns out.