For my off road riding, I have been using the Maxxis Ardent 26 x 2.4 tires. For the riding I do, mostly single track with a decent amount of roots and rocks but no huge drops or such, they work great. I keep the pressure low, so a ton of traction is the result. Mounted on a 26" Escapade rim (28 mm outside width) they measure out at 2.3" (58 mm) when inflated to 25 PSI at 82 ft above sea level.
Finding a tire that falls between 2.4" and 3" isn't easy, but we managed to snag a Surly Dirt Wizard for the experiment. We knew the 3" would not fit, but the 2.75 held out hope. It is labeled as a 26 x 2.75 " tire; when mounted to the Escapade rim, it came out to 2.63" (67 mm) when inflated to 25 PSI at 82 ft above sea level. So it's not a lot bigger than the Maxxis tire but enough so to be significant.
I'm not ready yet to ditch the triple, so in the meantime, I'll go back to the Maxxis tires for my off road usage, but this remains an interesting tire to try should the need for a really wide tire come up.