I was told maybe with a clutch kit upgrade. On the 500 26" tires are the recommended max. Potential issue is that the engine just won't spin them fast enough to clean out the treads in muddy conditions.
Driving slow in low gear and just rock crawling it ought to work. I would try it if I could demo some big tires just to see how it handled. ITP Mud lite 26" 12-12 tires are on my wish list. I definitely want a bit more ground clearance as well.