I've 5-boxed (noone else was there) it up to twin emperors. Did not manage to find a way to set my team up to successfully do twin emps (my tanking options were rather limited), but I'm pretty sure it has been killed by 5 single players before.
And just clearing up to that point gave pretty decent rep. Just remember to save the tokens from the bosses for later since you don't get rep from killing trash anymore after revered, and the tokens will come in very handy for that last part to exalted.