I looked into the WJ knuckle swap and it seemed like it made sense until I started pricing things out. I stuck to the stock system (@ 6" lift) and bought a BEEFY tie rod from Go-Fer-It offroad (out of North or South Carolina) and just lived with the TJ draglink (that's stronger than some XJ parts and the exact same as others). I bent the draglink a few times, but for what the XJ steering box is mounted too, I'd rather deal with the bent drag link vs. the steering box torn away from the 'frame'.
If I built another XJ, I'd do the same thing.
Oh, and that defys 'normal' XJ build parameters. You're supposed to brace the steering box to the 'frame', reinforce it and build a high-steer setup with WJ, Tera or ??? steering parts (all the while spending at least $1000-1500 or so on an already marginal axle). Just live with the XJ's limitations and have a good time with it. 33" tires on an XJ will do a LOT of trails and will be pretty reliable (with the possible exception of the rear axle).