Heh, for the time estimates, I was just going off what I've read/heard from other people. I'm guessing that could have been for 80 planets and level 7 AI.
So far I've been playing on low levelled AI as I get a hang of the game, but they don't seem to use much of the strategy the game is apparently good for. All I see so far is the AI massing units and then moving them to my planet. There have been times they had planets with lots of units sat there at one side of my little empire and they did nothing with them. Even when I attacked their home planet, they left the 3k or so ships doing nothing. Does it actually show a little more intelligence on higher difficulties?