Tonight, I decided to try out the demo for Space Empires V.
It isn't quite as fun as MOO II but it isn't bad. The UI does take some getting used to. It looks like each game could go on for a long period of time in typical space opera fashion.
There does seem to be a lot of community activity and developers have released a series of patches that helped to solve some of it's problems. There are several mods available for it.
Click to Enlarge Screenshot