If you look closely at three of the four Jeeps in the picture, the CJ, YJ and the TJ, you will notice that they are all drop right (passenger side).
So I'm betting that the running gear in all of them is from a CJ.
There is a thread from when the TJ was being built... Anyone care to find it and post it up here?
Come on, I'm not the only one that can use search (yep just being lazy, it's a challenge - find it).
For those of you too lazy... here's the pic: