Having lost a colony to *spoiler*, I then set up another colony on the same planet and moved on with life (using espionage on the *spoilers* - heh). Eventually, when I re-unified the planet, the only way I could find to really get them back together was using freighters. Lame, but it didn't take any significant game time to accomplish, really. Play time and micromanagement, yeah, but if you have a problem with that, you're playing the wrong game, eh? :-)