Wow, that slip yoke should be in the trans more for sure. How did you measure the length for the shop? I would not drive it until the problem is corrected, you could damage the tailshaft.
Damn. I wish it wasnt you sayin this Badsport... because I have too much respect for your mopar knowledge... which means I will likely have to concede the problem is the short shaft and spend more money getting a new (used) one and pay to balance again...
But thanks for your input BadSport. The truth hurts sometimes, but I need it.