Let's see. From the top of my head, I had longer games in:
Prepopulated:
Niua Simoa (my current game actually)
Mountain Lake (needs some minor adjustments; really fun though)
Pleasantview (the remake by Pleasantsims; needs lots of adjustments)
Bridgewood
Manave Isles
Huntsborough
Unpopulated:
Bellatrix (great for everything but scientists)
Cronor
Saturenorn (needs quite a bit of setup and is rather narrow in scope)
Great Bear (don't necessarily recommend it because of the routing; awesome lots though)
Mariners Reach
Paradise (well, it's tiny and empty, or in other words, special purpose)
Pigeon Rock
Some that technically fulfill the criteria are Strangetown, Mesa Grande, Amberville, Isle of Sims III, SimMeapolis, or Industrial Island, but those games were only test runs of an in-game week or so.
