Another possibility would be to run a couple of utility trenches in the floor away from where you'll park the bobcat, etc, with either 2by wood covers or metal covers. If its somewhat along the line of where you would line up the power tools (ie 1 foot in from the back wall with a "T" going through the middle of the power tool work area as an example) , that would allow you to change dust/vacuum and power hookups as needed. It would probably mean dropping the bottom of the utility corridor lower than the 6" slab you are now intending, and would be some extra rebar config, but it would minimize any ducting running across the floor. Sounds like a big project, regardless and it appears you are doing some good preplanning.
those both sound like great ideas, i like the wood floor one especially. what i would do is make a wood floor in the shop area, and concrete in the "recieving area," if you will. you see, the more i got to thinking about it the more i realized i dont need a 6" thich floor through the whole shop, just where i am going to drive in to bring in and take out wood. i need a big long drain and radiant heat to thaw lumber, logs, and anything else that might need thawing. in the wood floor i could have radiant heat as well, just stapled to the floor. i think i would use 2x4s as my joists and lift them 3 1/2" off the floor, so i could use 2x4 chunks on edge as "mini beams" every 4' or so, and if i ran them 12" OC i could get away with 5/8" CDX as flooring. with the 3 1/2" lift of the floor joists i could run any lines without cutting any joists, and the 4x8 CDX would peel up nice as long as i used screws spairingly, for easy access.
great ideas, thanks,
Would like to see some pictures as you go. Good luck