As was mentioned above, an off the shelf unit will work for the 4WD, I think I bought mine at Pep Boys. My trans knob is from an axiom, and took quite a bit of work to make it fit. This picture was taken before I shortened the shift lever from the transmission to make the handle trim ride down flush with the cover around the bottom of the lever. I believe most of the shift knobs made for an automatic with a "push to unlock" feature will work.
"If you're not living on the edge --- you're taking up too much space!!"