What is the maximum level for the Multiplayer Campaign?

I think there is no max level. Yesterday I saw a Chaplain with a level of 175.

193 is the highest I've seen so far.

On a relevant side note, in my personal experience, (Level 76) you have enough renown to fully kit out a class with a custom weapon with armour and perks every 25 levels.

Somebody went 250 in closed beta....
I won't out them. They probably want to maintain the illusion of having a life. 😉