I would try out Velks, something like camping both Frenzy camps. You should be able to tank anywhere from 2-4 depending on the rogue's and cleric's gear. The advantage to this is that these are about the weakest hitting mobs that you can find and still get decent experience with.
Recently I PL'd my rogue from 57-61 in about 1 day played there, I would get 1% a kill, except in 59 when it was 2-3 spider per 1%. Simply put they hit weak and you don't have to worry about them getting some insane RNG hits on you.