I got a lot of 2-keyword BDSM-niche domains. Many of them are very nice-sounding and could be easily developed, which is what I work on when I'm not fucking around on GFY or playing my internet spaceship game.
My current experience is that there isn't much market for undeveloped domains that don't get multiple-hundreds of type-in traffic, not right now. There has been in the past (people want the combo of brandability plus an easier SEO job) and I think there will be in the future, but right now it doesn't matter how cheap you price them, they aren't moving.
I personally would rather hold a domain like asscanings.com (to throw a dartboard at my portfolio at random) than sell it for $25 or $100. It got like 150 page views last month, about half type-ins and the rest from search. My stats aren't granular enough to tell me if it paid for itself, but I'm maintaining my portfolio without outside cash so far. There's enough value in the traffic that I just don't feel any incentive to sell for peanuts. And nobody's buying at higher prices. Would I sell that domain for a grand? Probably. But there are probably cheaper alternatives available.
I drip a few domains out on NameCheap Marketplace every now and then, mostly portfolio-cleanings that don't match my always-changing views of what's good to own. Sometimes they sell, mostly they don't. It's all good. I believe in business cycles, and I believe we're in the bottom of one. Whether it takes an economic upturn or another as-yet-unforseen structural change in the porn business (more likely both), I dunno. But unless the internet changes how it works first (possible but, I think, unlikely) a big pile of nice domains will be a valuable asset the next time the cycle turns up.