Still could be the shaft. Have you lubed the centering ball of the double-cardan setup yet?
It's that well hidden female zerk fitting that you need the male needle attachment for your grease gun to lube.
What have you done to the rig lately? Did this just start coming on slowly? Or did it happen after a lift kit or other suspension mod?
And even without excessive play, the joints could be dry or over-torqued (the rear one anyway) and cause funny noises.
Can't say for certain that it's the shaft or joints of course, but in my experience at least, u-joints going bad can make as many different sounds as there are times you have to change joints! No two u-joint issues seem to give the same clues.
Paul