No rear shaft, no front shaft, as long as you have one or the other. Surprisingly no one has noticed that my truck doesn't have a front shaft for almost a year now.
Judging from the Craigslist and Ebay sales of partially completed project trucks (and trars, and other monstrosities) lacking one, it's not only possible but commonplace for mall crawlers to run without a front shaft.
Actually I think it's poorly thought out suspension when the bozo booger welding the thing wakes up after a PBR-fueled weekend bender and realizes that no U-joints in the known universe will run at 75* angles and so gives up on the project and dumps it on the next poor shmuck.
-- A

I just don't have the front one cause the money keeps going to other repairs. 