Here's the details on the twin stick shifters & linkages:
First I cut the factory link bar in half, flipped the rear shift bar, and ground down and reinstalled the front shift bar. I used the factory hole in the rear shift bar, and made a new hole in the front shift bar(had to cut it with a torch since this piece is apparently hardened and I didn't have the proper bits to go through it.)
Next was the linkages. The linkage on the left was the factory one, the only change to it was to heat and straighten it. The linkage on the right is the one I made, using 1/2" round rod.
Here's the completed linkages and bottom of the shifter assembly. I cut the bottom half off the factory shift lever assembly and used it for the rear shifter (the inner one). Also, I cut off the excess bushing/tube on it and used it for the bushing on the new front shift lever (outer.) The outer shift lever was made using 1/4" plate. Both shifters hinge on the factory bolt, and used the factory plastic bushings.
Here's the completed shifters, made from 1/2" rod.
Next was to cut out an adapter plate to mount the shifter boot into the factory location:
Here's a picture of the final installation. I used a Dana 300 twinstick boot which fit perfectly around the 1/2" dia. shifters. I welded a fine thread bolt (can't remember dia.) to the top of each stick so the factory shift knobs would screw back on:

(I still need one more factory shift knob, so if anyone has one let me know)
Next step is building a 1.5" .250 wall tie-rod and drag link using GM 1-ton TRE's. Hopefully I'll get to that fairly soon.