I don't know about the other servers; but Siege Perilous used to have a pretty active shard war between the Wakayama Clan (made up of the loyalists to Britannia), and the other player-communities of the shard. Their guildmaster essentially proclaimed himself king, and demanded that all other player communities (Wispwoodshire, Iantown, etc.) swear fealty to him and pay a tax. It was actually pretty neat, because even some of the PvP Guilds (TnT, VmP) got involved.
On Baja, it looks like some of the remaining roleplay villages (Dawn, Avalon) and Lord Casca are going to be coming to blows in the near future. Casca demands fealty of all independant and sovereign states; and the Grand Duchess of Dawn has no intention of bending knee to this "upsurper." Our communities is extremely small and divided; but we might see something happen in the future. It would probably be less PvP, and more PvM though; unless the Sosarian Inquisition grows large enough. I would love to encourage roleplayers to come to Baja; but I can't promise this great roleplaying scene until we've had the chance to grow a little more.
I would also check Atlantic and Catskills. They have a vibrant community.
