Don't really read much which gives room for interpretation along these lines, wrong genre for me, but have seen a few anime which would fall to question. There are the obvious like Oreimo which I found interesting till it went too far, but most simply hint at a strong bond or no blood relation. I think most of the problems which the general population has with the issue, referring only to books or television shows, is coming from their own inferred idea of a relationship rather than just friends/acquaintances. People are fast to jump to conclusions that more is happening than is being read/watched just based on a close friendship. For example, even though nothing beyond friendship has ever happened in Love Live (unless you read fan fiction/doujinshi) I've seen references to the series being yuri. This isn't to say that series which actually cross the line don't exist, but rather that people tend to try to read more into the material than is actually there.
In a different context, although the beach episode is a common trope, sometimes you just want to go to the beach. Don't get me wrong on this one, A LOT of shows use this trope for a chance to add ecchi tones without really crossing the line. However, although less commonly used in this format, it's just about getting away for a vacation/break away from the normal hum-drum. If you're looking for an instance of this, Himouto immediately comes to mind, and for what it's worth, is even a series about a brother and sister where there is absolutely no physical interest from either of them.
Just being close with family doesn't equate to incest, and I feel that a lot of people want to jump to that conclusion. There are series, some rather popular ones, which do cross that line. However, inferred meaning doesn't equate to reality.
