It doesn't deal with them joining the Federation, but Spock's World
is an awesome piece of world building for the Vulcans. But just to warn you it was written in 1988 so it's history doesn't entirely line up with what was revealed in later series. If that doesn't bother you it's definitely worth a read.
If you're interested in ongoing stories, there is a lot of development given to several major worlds in the DS9 Relaunch