I had the same noise coming from the front end - and believe me it IS the front end that is grinding, 4x4boy. My VX is lifted and the noise was coming on at random at accelleration and at higher speeds if I let go of gas.
Few weeks ago I grenaded my front differential. We disconnected my front wheels and front drive shaft. I made it to Chicago, around 120 miles, without any noise.
4x4boy, if it's not your driveshaft, the culprit most likely is your differential. There was a couple of other members on the board that had simmilar problems with griding noise, and some of them ended up replacing front diff...