That's a great question. Specialized doesn't have a 29er MTB Armadillo. Specialized 29er frames are so sluggish, I don't think they sell enough bikes to justify it. I have never seen a knobby 29er tire with built-in flat protection. I'm using the StopFlats2 Purple liner, slime tubes, and thin/light stock Bontragers on my Fisher 29er.

I'd say Big Apples for a fattie road tread 29er. I had pretty good luck with Apples on my Cross Check last Summer and Fall. One flat over 6 months and about 2000 miles, I took them off because they were too fat for my fenders to fit properly.