I am starting my floor project next week. I posted the same question a couple of months ago and am tentatively planning on doing it this way. Vapor barrier, 2x4 dry PT 2x4's on 16" centers, but the 2x4's will be cut no longer than 3' and positioned so that the butt joints are not opposite one another and allowed to "float" (no tapcons"). The guy that recommended this said he was advised by professional gym flooring installers to do it this way. I will cut some 1/2" ply up into 3 1/2" strips and place that on top of the 2x4's to make the depth 2" and then place the rigid foam in between the 2X4's. Then the 3/4" subfloor and last a utility grade hickory 3/4" floor from Lumber Liquidators. I have the wires coiled up against my shop wall to run under the floor for my Table saw (220 volt) and also for a 110 outlet. Unless I change my mind (I may just put 1" foam down and not build up the 2x4's to 2" think) this is it.