I played some Die Macher.. Pretty long, but not quite that long. Also, some of the 18xx games can get pretty long.. But still, 7 hours? No game should take that long.
I'm actually not quite sure about Cosmic Encounter - Its barely actually a board game in the first place, I feel like strategy is only barely there. Dont get me wrong, it does well in the bluffing and luck department..
I tend to prefer Eclipse (or, Space Empires the board game).. But those are slightly deeper than CE.