Being as someone that has invested a good deal of her money in yaoi manga (though I prefer the term boys love), I'll explain some things as I, personally, have seen them. Anyone who has evidence to the contrary is certainly welcome to correct me.
1. It is not generally considered accpetable to like boys love in western culture. Some women and girls do find it attractive...but there are also many more that tell you your weird for liking it...and telling a GUY your into is....well it's really fucking awkward and all of a sudden your the creepy girl from The Loved Ones movie in their eyes. (In fact, I've heard things to indicate that it's not all that acceptable in Japan either, tolerated, but not well liked, but having never even been to Japan, this is only hearsay so take my words with a grain of salt and anyone who can confirm or deny is welcomed to do so.)
2. It is not very widespread in the states. I have even known anime and manga lovers who had NO IDEA what I was talking about when I mentioned popular boys love titles such as Ai no Kusabi and FAKE or even the word yaoi. If your not part of the group, a lot of times you don't hear about this stuff. Seriously there is such a thing as a Yaoi Convention and I wouldn't be surprised if hardly anybody on the escapist, some of the nerdiest of the nerds, had any idea it existed.
3. There is a lot of "rape but it's okay because he likes it in end" style of stories in boys love. I will admit it, even if others will not. Note that the rape is rarely done in any kind of malicious or hateful way, it's usually the thought of "I'm just showing you that your really gay" and I feel that this shows that the author and audience aren't intending for anyone to really be hurt but that doesn't really make it any better, rape is rape. I can only assume that this storyline is generally done because it's a cheap and fast way to get a story out and make money and I admit I read a lot of it...when I was younger and didn't know any better. Giving credit where credit is due though, this is not ALL boys love ever is, if you find a good mangaka you can get really good stories with in depth characterization and motivations and sweet, romantic love stories or drama or angst or whatever your into, but you gotta wade through a lot of shit to get to it.
NOW whether or not you would make your money back on a boys love movie, which there is some evidence that you might, seeing as movies such as Brokeback Mountain and Magic Mike did well I believe(not saying that either of these are ANYTHING like boys love), it would still be a BIG risk and while the controversy that came from it (and there WOULD be people screaming in the streets and waving around signs) might be good...it could also really fuck your studio over, especially if people feel your movie is portraying men being raped as okay, which it most certainly is not.
Honestly I wouldn't want to see a big budget hollywood boys love movie because more than likely it would either be very stereotypical...or incredibly bland so as to do it's utmost to NOT be stereotypical.