I have had no losing months in 07 or 08 so far, although I have had quite a lot of losing weeks.
My game is probably 80-85% MTTs, with a few cash games thrown in and an occasional STT.
I would think that losing weeks are to be expected for a MTT player, because of the high variance. However, if you are a successful MTT player, you are apt to have at least one big win each month, which wipes out the small losses.
On the bad beat issue, my experience as a MTT player is that the better and more successful you get, the more bad beats and suckouts become part of your daily life and you just have to live with them. Logically, if you are a sound player and rarely make errors, your tourney can only end in one of three ways:
1) You reach the FT and make a big payday.
2) A train wreck - you make a play with the near-nuts, knowing that you are statistically a strong favourite, but luck dictates that the opponent has the rare hand that beats you.
3) A bad beat - you make a play with the best hand, opponent makes an error and calls but gets lucky.
So, as you eliminate errors from your game, the percentage of tourneys where you crash out thanks to a bad beat grows. Thinking about my own experience over the past couple of weeks, I would say my results break down roughly 10/20/70. In other words, I finished high in 10% of my tourneys, suffered a train wreck in 20%, and went out to a bad beat in 70%.
So you see, bad beats are very commonplace and just have to be shrugged off.
Oh, and I made a bad call in one game, but we won`t talk about that.