Too many variables to say how hard it will be to find. From what I've seen though, the monitor accounts for a good portion of the price. IMO, unless EVREYTHING ELSE was mint condition, no deal.
That being said, it really depends whats wrong with the monitor. If it's all intact, and the tube isn't burned up, it still may be worth your while, as long as you can either a. repair the monitor boards yourself, or b. justify the expense on having them repaired.
For my money, if the game played blind, and the tube wasn't burned, I'd buy it, regardless of the cabinets condition. As long as it was complete.