So it only makes the sound for a second after you start moving? It almost sounds like the brake shoes are binding up inside the drum. Hard to tell though as the engine noise drowns out alot of the actual sound. If a wheel bearing was that far gone to make a sound like that I would think it would be heard all the time. Pull your drums off and make sure all the brake hardware is still in place and that the shoes haven't fallen apart in there. It could very well be a bearing but again, it's hard to really hear the sound.
'84 CJ-17: 17" stretch, locked Toy axles, 5.5" lift, FI, AX15, D300 w/twin sticks, boatsides & junk.