Well you can already find a few flash in the states, but primarily smaller ones with a lot lower quality. Can find a few on "Newgrounds" for instance, and I am sure there are others out there.
I would probably buy one myself, as long as it isn't a really bad one. I am actually pretty sure some are made in the U.S., but idk. Of course this is a very big maybe, since you can buy plenty of the overseas ones and you can buy the translators for them, or whatever they are called.
On a side note, a think they do click with the audience in a sense. It may not be as big, but if americans can love ecchi and hentai, why not love a game featuring it?