I am a writer in the QL novel program at Berkley books. The
enclosed novelists' guidelines, written
by editor Ginjer Buchanan, give the general requirements for this
program.
The writers' FAQ discusses canon from the
point of view of writing derivative fiction.
Some of my non-professional fan
fiction, including three back stories, and a post-"Mirror
Image" story, is available here.
My post-"Mirror Image" fan novella, "The Return," is available
from Jim Rondeau's Buffalo Chip Press.