it could still be the CV joint(s). maybe the torque applied to the joint when you're pressing the gas pedal is enough to cause the clicking, but just coasting (no gas pedal) isn't? just a guess..

the CV boot also doesn't have to be ripped or visibly damaged to be leaking. check for signs of leaking on and around the joint too, even if it looks alright. if you know a mechanic that'll put it on a lift for you, they'll probably be able to tell in a couple seconds.