Hi, am i member of civ3players ladder, and i've played over 500+ ladder games, All different scenarios, i've played standard ancient, Medieval, Industirous,Modern starts, team games QC , 1vs1, epics, the only problem with MP is that #1 its very unstable, and #2 it takes to long to get anywhere, but what i've been playing recently are 1vs1 non accel prod continant epic games and they rock.I play with friends who are dedicated to finishing them, we save and reload whenever, we can somtimes get up to industrial age in 1 sitting,normally takes around 6 hours, but it is extremely worthwhile.and you get a feel for the 'full' civ game, as opposed to normaly 100turn 3 hour ladder games that are getting tedious now.
as for a bigger game i would strongly recommend that you have a 6 player limit this is to help with the flow of the game, and to avoid major lag drops OOS that would over time ruin the game and the fun and the effort put into it.