>* Are there dust filter systems in such Nikon camera bodies?
>* Is it looking for trouble to use pumper type lenses outdoors >in sometimes dusty locations like Renaissance Festivals?
>* Is dust collection inside of camera bodies a significant >worry?
>* Does dust which enters camera bodies due to operation of >pumper type zooms eventually get sucked into the zoom barrels >too?
Yes! The lenses are not air tight either. In fact I suspect that most if not all of the air entering or leaving the system will enter through the lens and not the camera body.
>* Is professional cleaning of bodies and zooms to remove dust >ingested due to pumper type zoom lenses a know routine >service?
>BOTTOM LINE: When in a dusty environment like a Renaissance >Fair will using a pumper type lens like the new 24-120 F/4 to >avoid changing lenses gunk up the innards of my new D4 worse >than changing trinity family lenses at the Fair?
You are over thinking this. Just use common sense. You are more likely to get dust in the camera if you change lenses is a dusty environment. With the exception of underwater cameras, No camera or lens is air tight. The D4 has the best dust sealing in the Nikon line of DSLR's. Have you had a problem with your D300?
>Is this dust entry into the camera body enough of a problem to >avoid using a pumper type lens in such an environment?
Use the lens or lenses that works best for your needs. Cleaning the sensor is not that difficult. Good Luck and Enjoy your Nikons!