Had a set of nice OEM housings and the switch from 1Fastbrick sitting around here forever; finally got around to doing mine today, used the bracket info given in this post -> http://www.silveradoss.com/forums/topic/86458-how-to-install-your-fog-light-wiring-to-factory-switch/ - my truck being an '06 the factory wiring is already in place so I just needed to make brackets and add the parts.
I used plain 1 x 1/8" steel flat bar to make the brackets. Thought about using aluminum and it probably would have been fine at that thickness, but I wanted to be sure they wouldn't flex at all. Used cutoff wheel to zip off some 5" sections then drilled the holes 1/4" with one end a little offset as shown in that thread, then cleaned up all the edges with the die grinder. Even with the 1/8" thickness I was able to attach them without issue using the studs poking up from the bumper cover brackets above the brake ducts. I used stainless fasteners since they sit right above the lens, didn't want moisture causing any rust to drip down on them.
Mocking up the bracket using a piece of cardboard just to be sure
First set made, checking the fit and operation
Side view behind the brake duct, I think I want to cut out some vinyl to cover up the excess lens area and prevent light bleed-through around the duct
Other set made, both lights in place and operating
Popped 'em back apart to paint the brackets to prevent rust, now that I know they fit how I want them to
Easy job...next up I'll order either some high power LED's or maybe HID's to go in them; probably go with LED as HID seem to be obnoxiously bright in this application.