Two switches between power and lights
Well, I'm sort of an "out of the ordinary" kind of guy.
Actully, a part of what lead to this solution was not being sure how much light this new playroom/den is going to need. With everything moving to CFLs, I don't want to install dimmers. So I decided to convert the ceiling lights to logical "three-way" lights. Basically, I'm going to install ceiling lights fixtures that contain two bulbs. I'm going to install one 40 watt and one 60 watt bulb in each fixture. I'll run 14/3 to the fixtures, and power the 40 watts from the black and the 60 watt from the red. The primary 4-way switches will power the switch bank. The switch bank will independantly power the black and red of the 14/3. That way, without any special hardward, I'll be able to have lights in the ceiling powered on at 40, 60, or 100 watts (or what ever pair combination I want to put in the light fixtures).
I could extend the logic to make 7 way lights by using light fixtures with three bulbs. I could fill each light fixture with a 25, 40, and 60 watt bulbs. That way, I could have 25, 40, 60, 65, 85, 100, or 125 watts of light. But the additional wire and multiple combinations on the switches makes that idea a bit over-kill.