Wouldn't it be possible to take sound-bits from the actual series to use?
I don't think we could find enough of the right sound-bits from anybody except the well known characters though... I think some people would find it a bit jarring to suddenly hear their favorite characters out of nowhere when they click on some nodescript Steamrunner class or something...
I
was going to suggest we give some of the sound clips from Star Trek: New Worlds a try. Lousy game, sure, but some of the voice acting for the various units was actually pretty decent... Unfortuneately, retrieving the sound files might be more trouble than it's worth because New Worlds has this very strange way of storing its infomation files. Most of its sound files are simply wave files that are plainly visible when you go into the New Worlds program files, but a few (including, unfortuneately, all the voice sets for the units) seem to be
missing from the files, even though they play when you go into the game...

You might be able to get them off the disk though... I don't know...