There's quite a wide variation in how fast monks have got to 40 spells (by level 40, level 70 and not til after cap have all been done) but I'm not aware of anyone going much beyond 40 spells before cap. (1x spells to high level tested out ok in the beta, but the beta was a lot more favorable to monks than the game is)

If you just mean monks that use magic in the way a magic rogue would, pretty much every build that has been posted does that. I don't know any monk that uses magic as the main killing tool rather than as a major set up tool and wouldn't expect it to work well at all. Not quite scroll warrior territory but close.