If you're OK with stuff that bridges genres, let me recommend Tad Williams' 'Otherlands' series. It's largely set inside a massive virtual reality universe where thousands of people have created their own mini-universes based on whatever theme pleases them - which is where the fantasy elements come in, because the protagonists venture through areas that echo Alice in Wonderland, the Wizard of Oz, ancient Egypt, all kinds of stuff. One of the main characters has progeria. Another is a psycho killer. Seriously, I love this series to death.
I liked the series overall, but felt cheated at the end; the inciting incidents at the beginning (like what was happening with the children) were not satisfactorily explained (if they were explained at all). I would have to re-read the series to be more clear on what I mean; my first and only read was like ten years ago. I do own all four volumes in hardcover though, and plan to reread, because it was a wild ride, and a damn sight better than The Lord of the Rings or The Dark Tower.
