I am currently in a game agaisnt 2 lvl 7 AIs, sitting on a fleet of over 7.000 MK2-4 ships and I am now adding starships to the mix. That is at 6 1/2 hours of game time. I started with 3 home planets so the 7.000 is close to my aboslute max for ships, but I have yet to upgrade one ship type and capture one tech so I could get my fleet up to over 9.000 xD
I have about the same points as the AIs have combined and from the graphs I have more MK2, 3 and 4 ships then they do individually. I think if I just took my 1.600+ Raiders out right now, I could bomb the AI progress all the way back to 1 by destroying all of the datacenters that are left. Id loose the lot of them but it might be worth it...
I am not really complaining, but I dont really feel at a disadvantage compared to the AIs right now, not like it was with one planet.