My 900M on MM gets me a meager #170 something I think...I wouldn't say that MM is a hard table though.
When it comes to "Beating the game" I would probably say Medieval Madness and the Battle for the Kingdom and winning in Champion Pub (incredibly difficult!) together with a few others that I probably forgot about.
Do you play the (regular) MB over and over to rack up extra balls from the super jackpot?
What? That only gives you an EB the first time. I am 99% sure (I have played it 500+ times)! Or, have I missed something significant here?
Regarding Goin Nits, there is a way to backhand the captive ball. It's tough, but doable. It'll go right inbetween the pop bumpers, and missed shots will come right back to a trap on the left flipper. So if you can get it within 50 seconds every time, you could theoretically go for forever.