I wouldn't rush off to buy a 6.7 yet either. They have only been out a few years, and while initial reliability seems good; time will tell. Remember that the 6.0 seemed great at first, then people started having problems. I'll bet there are a handful of 6.7s out there with over 100k on them, but probably not many. These things need to be used and abused for a while before we go along with Ford claiming that they've finally solved their Diesel problems. The 6.7 has a lot more complexity to it too, and that in my experience is never a good thing. Reliability comes from simplicity. The 6.0 is too complicated in stock form, so I don't see adding more emissions stuff and other things that can fail as a step forward. Think about it, best Diesel offered in a light duty truck? 5.9 Cummins 12v with a P-pump. 100% mechanical, easy to work on, easy to tune, and cheap for a Diesel. Emissions were that engine's only issue, otherwise Dodge would still run them.
I'd love to know what specifically over and above what I've noted for bulletproofing would need to be addressed. Three large Diesel service shops around here who work on a lot of 6.0s all seem to agree that once you take those steps the problems stop. Injectors can wear out, as can other things, but that can happen on any Diesel. Ask anyone who really knows about Diesels and they'll tell you that injectors makes a major difference in how a Diesel runs and they usually last 100-150k. They may go longer before outright failure, but to keep a Diesel running smooth you're going to want to swap injectors somewhere in that time frame. Yep, they're pricey, but what on a Diesel is cheap? Frankly I don't chalk that up to failure, that's maintenance.
'06 F250 4x4 - 5" Flo Pro exhaust, SB Filter intake, Accufab elbow, Edge Evolution (monitoring only), SCT w/ ID custom tune, FASS 195 pump, Gillette Diesel EGR cooler delete, Sinister Diesel coolant filter, ELC coolant, updated turbo drain tube/oil feed line/STC fitting/oil cooler, ARPs w/OEM HGs, Elite coolant lines, ITP RR fuel system, RCD 175/30 injectors, Powermax, BD CCV, FICM.com FICM w/ ID tune, Elite UP, BPD water pump - 13.069 @ 101.94
'02 WRX - Outback rear disc swap, EBC green pads, DBA pillar vane rotors, TXS UP/TBE/TMIC, Perrin LW crank pulley, PPG billet steel shift forks, ACT Streetlite flywheel & clutch, K&N filter, STi Group N motor/trans mounts, TiC/Kartboy rear diff mounts/subframe lock bolts/outrigger stiffeners, Kartboy SS & all shifter bushings, custom PDX tune for Cobb AP - went 14.1 on a terrible 60ft before most of these mods; shooting for 13.50s