wow really is an appaulling game for rp I'm afraid. Can't say anything for any other server but Defias Brotherhood has it horde side if you join one of the single race guilds.
Second Gurubashi Empire (Trolls), The Old Lordaeron (UD), Orcs of the Red Blade (Guess), Mistrunner Tribe (Tauren), others floating about. From what I hear there's a fair amount alliance side aswell, but being a pvp server I've not personally experienced it.