Henry J - I will definitely keep everyone posted on my finds and end solution.
Stucky - I looked at the outrigger mounts you referenced, but unfortunately they wont do the trick. Thank you for the info nonetheless!
ApproachMedium - I went back to the upfitter's manual after reading your post. I was hoping I missed something, however according to the manual, the rearmost mounts on the crew are in fact different from the extended cab. Looks like the closest possibility may be a 4-door Blazer, again, according to the manual. I know that quite often I find that just because it is on paper, doesn't always make it so. I suppose I should go root around the junkyard and see what i find. Thank you for your suggestion!