I think some have said its under the bezel where the front-camera is (as it decreases the WiFi's reception depending on the signal strength when covered).
What are you talking about? The Wifi and bluetooth came from the black plastic piece on the back of the iPod touches. It only came from the bottom for the 3G and the 3GS.
The antenna for the iPod touch 4 is at the front panel near the front facing camera, according to iFixit.
I think some have said its under the bezel where the front-camera is (as it decreases the WiFi's reception depending on the signal strength when covered).
from the teardown photos the wifi antenna is (looking at the back) on the top right edge (reaching from the edge to the middle) just higher than where the camera in on the left side.