I believe what M_S says is correct. The Kona fork on the Sutra has rack eyelets on it. Put that fork on a Specialized Crosstrail, which has rack in the back, and mount 29er tires on the Crosstrail. That's an option you might look at.
I recently ordered a Marin Hamilton at REI ($340 on sale now). I test rode a Marin Muirwoods they had in stock, as it's basically the same bike with gears and discs. The fork is suspension-corrected and has big tire clearance. The back isn't as generous, but it looked like a 2.1" tire would work. REI didn't have any 29er tires to try.
It's stock except for the rack and pedals. I also swapped the stock 15T cog for the included 20T cog. I didn't buy it for off-road duty, but I rode 15+ miles of singletrack with it yesterday. It's quite capable, but my hands would appreciate a new fork and some fat tires.
I have a front Old Man Mountain rack that uses a longer skewer on the lower legs and the top of the rack goes on the canti braze-ons under the brake arms. If you don't already have a rack system and want to part with some cash, I recommend them highly. I haven't actually ridden with them, but once they are mounted you can see how strong they are. The guy who sold it to me has toured on them extensively, as well as other racks, and he really loves them.