Never say "never" or "allways" with Fords. They allways seem to find a batch of old dusty axles or brake boosters sitting in a crate hidden in the corner of the factory in the middle of a production run. "Hey let's use these!"
6.7's have a vacuum pump on the engine. It's used for the EGR and wastegate I believe. I'd assume that there are still some AC controls in the dash that possibly run on vacuum still as well.
I'm scheduled to test drive a used 2008 F250 XL Ex Cab, Longbed, 4x4 towards the end of this week. If it isn't sold by the time it's my turn to test drive, it's mine. I'll take a look at the booster. I prefer the hydroboost, but really have no problems with vac boost as long as the vacuum pump is replaced every 90k miles.
2011 F250 w vac boost brakes and the diesel 6.7:
Also keep in mind that Fords spec books and parts manuals are far from gospel. Remember the 37 spline 10.5" rear end axles that are supposed to exist?
2007 brakes spec list (copy/paste):
Front 13.66-inch disc
Rear 13.39-inch disc
Assist type Vacuum (F-250/F-350 single-rear-wheel gas engines) / hydro-boost (F-250/F-350 single-rear-wheel diesel engine, F-350 dual-rear-wheel), ABS