Personally I would love to see more black girls and especially girls with a really big booty. I know from where I live that I'm in the minority with that opinion though. Most people I know like the fit, small, white / mostly white, medium ass, etc. Then again the majority of people that live here are white (including me). My guess is that most people prefer someone a little similar to themselves. From personal experience, I see the same thing in predominantly Asian or black countries. A shame really but I guess you can't argue with what turns you on.
Now, my guess would be that the overal user base of SLR has a demographic that leans toward liking the white teen kind of look but I'm just speculating here. Just hoping there will be some more room for black girls too cause there is way too little content for them even if the majority of users here have a different type.
Also, a bit of a rant here but I find the term "black" in porn super vague and unspecific. It's like saying that you like European chick's or something. Also, most girls in porn that are classified "black" are mixed race, sometimes even Asian (now more often than not I like those girls too cause mixed race can be insanely sexy) but what I'm trying to say is that if your type is a dark skinned woman with a certain ethnicity than it's similar to liking Italian girls from my Europe analogy. It's kind of a niche in a niche and if you like a big booty than it's a niche in a niche in a niche. Which is weird cause I don't think it's much more specific than liking milfs with tattoos or something. In reality this means that the type of girl I really want to see more of is almost never cast. Hope that that will change though!