You could just wait until something breaks or falls off or until the noise becomes so loud it becomes obvious what it is.
when I call my mechanic, Joe, for advice on what to check about strange noises I'm hearing from my jeep he tells me to put it on jackstands and use the process of elimination like what your doing.
can you put the front up on jack stands and turn the front tires by hand to reproduce the noise?
removeing the front driveshaft and then take it for a test drive to see if the noise continues as part of your process of elimination.
then test if the noise is from the drivers side axle ujoints and pull the assembled inner/outers from that side and replace it with just a spare stub shaft and then test drive to see if the noise continues (or if you have fully assembled spare, swap those in)... if noise continues then do the same swap on the passenger side.
if you don't have a spare unit bearing you could buy one for around $75. It would be good to carry an extra one on trail runs anyway. Or buy two and install them and keep the old ones as spares (I actually did this cause my local shop was selling them for $60 each). You could remove one of the front unit bearings and replace it with the new one on that side... if the sound continues do the same on the other side with the new unit bearing.
You may also want to look for the noise at the rear of the jeep... with jeeps it can be very tough to discern where the noises are comming from while sitting in the drivers seat. so you may want to put the rear on jackstand and continue the process of elimination.
maybe youve just got a bunch clay mud sucked into the rear drums. with the front tires chalked and the emergency brake off, remove the drum (or hat if its a rear disc rubicon) and without removing the shoes, just visually check it out.
thats all I can think of at the moment.