I put in a floor shifter when I installed the 700r4. I just cut the shifter arm off (console one), replaced the piece of plastic that had the PRD321 with one from a manual tranny explorer.
I used a b&m cable shifter.. Its not bad.. Not as precise as my factory shifter. It did come with a reverse and Neutral safety switch but the netutral switch died in < 6 months (I now have it wires so it thinks it is always in neutral)..
I got the shifter for < $150.. I was thinking of getting a Lokar shifter (linkage, not cable) but it cost more and I didn't want to do that much cutting.
The issue we did run into was that the floor of the truck is thin where I wanted to mount the shifter.. Its the metal you take out when you have a manual tranny. What I did was drill 4 holes (2 are in the thin metal). We then welded a place across the bottom of the truck and welded nuts to it. Now I can bolt the shifter in without having to get under the truck. We had the tranny removed when we installed the shifter.. I don't think we could have welded it like we did with the tranny in the truck (even if we lowered it).
~Mark