I've noticed there aren't many for RD, which is understandable as it's difficult to do justice to more than one fandom in the same story whilst also coming up with a plausible reason for two or more sets of characters to encounter each other. Probably the best one I've read is this gen "fusion" fic which casts the characters of BBC Sherlock as those of RD. Definitely worth a read if you're familiar with both fandoms, but bear in mind it doesn't actually contain any RD characters. http://archiveofourown.org/works/576769