My colleague Prof. Bainbridge has a post about the use of law, especially law other than criminal law, as a plot device in fantasy books. He thinks there's relatively little of it, and that's my sense, too (though of course I'm limited by what I read); I'd say the same about science fiction. Christine Corcos, writing in the new Law and Magic Blog, thinks there's actually quite a bit out there.

I think all three of us would agree, though, that this is pretty fertile ground for fiction: The legal fiction genre (at least at its best) shows that law can provide interesting plot twists, an extra source of drama, and a means for showing and developing characters' character traits. In fantasy/SF, it could also show and develop the implications of the new rules or new technologies that the fantasy/SF author is introducing. I'd love to read some first-rate works that combine the genres these ways, or even just introduce some legal elements into the fantasy/SF genre (though I recognize of course that schlock can be written in this mixed genre at least as well as in the individual genres).