Since the original set came off my XJ, I used a set of Timkens and they really didn't last that long <30K> before I detected that they had a grindy feel when turned by hand.
A couple things came to mind. The first was that I wasn't torquing to spec. The torque spec for the front hums is actually very hefty because it hold the hub together. The second is that since the 86' hub I put in on that rig, I haven't seen a real nice seal on the inner side of the Hub. The early models you could buy the seal separate, the new ones don't have it <don't need it?>
Hub failures never seem to be catastrophic unless the shaft that goes through the hub is not installed, then the bearing will separate and cause loss of vehicle or life. So warranty lenght will not matter whether you get off the trail or not, neither will the manufacture.
Lastly, NAPA sells a Hub for an XJ for $72+ Tax. It is not their lifetime warr one, but it has a year warranty. Rockauto price for a Timken set is currently $92 + shipping. I bought my last set from NAPA. So far no problems.