Thank you so much for putting this community together!

First... There's something odd in the cut-code... viewing this comm's main page via http://newbieguide.dreamwidth.org/ shows this post only having fandoms down to DC Comics.

Second... There's a shedload of new Star Trek comms springing up like mushrooms... you've already got
startrek: Star Trek: The Final Frontier: A community for general fandom discussion of Star Trek in all its forms
but I'm also surfing around finding things like these:
kirk_spock: Dedicated to the Kirk/Spock pairing (classic and new)
kirkspockuhura: Kirk + Spock + Uhura OT3
mccoy_chekov: Old school, new school, RPS - we wants it, as long as it's McCoy/Chekov or the respective actors
ncc_1701: Fan works and meta based on J.J. Abram's Star Trek (2009)
singularity: A community dedicated to fic based off of the new Star Trek (Reboot/2009) movie
starry_sea: Star Trek, old school style.
star_trek_flashfic: Star Trek Flashfic
startrek_reboot: Star Trek is cool
suluismycaptain: Fic, meta, art, and more about Hikaru Sulu.
thetroublewithdrabbles: Star Trek (2009) writing community -- 100-word drabbles
trek_news: A fandom newsletter for all incarnations of Star Trek
trekfics: Fan fiction from all incarnations of Star Trek
trek_kink: Star Trek XI Kink Meme - Fic meme for Star Trek XI
vulcanreforged: Stories about the effects of the Nero Incident on the Vulcan species and the Federation.

For the actors, there's
chris_pine_daily: A picture (or more) a day of Chris Pine

And so far I only see one RP comm...
reversepolarity: A Star Trek TOS RP Comm

And I have to mention this one although you may not wish to add it... holy crap, I am amazed that there exist people in the world who are on Dreamwidth but who have not previously seen any Star Trek episode or film anywhere. Whoa, that is brainbendy...
star_trek_virgins: Making our way through all Star Trek Episodes

Hope this helps!