I don't have a rear bumper on my 4x4 79 and I think it looks just fine. I have mud flaps on the rear just behind the tires, but I only needed two more inches lower than the rear of the bed to be legal here in OR. If I didn't have 2 inches of the lift or had stockish sized tires on I would fine. I got pulled over for it once before I put on the flaps, and the rule at the time was something like no higher than 24 inches of exposed space behind the rear tires. That was after 5 years of driving it that way and never having it brought up in more than a couple traffic stops.
Back when I'd offroad my 2WD 76, I always had trouble dragging the bumper more than anything else, so leaving it off just gave me that much better departure angle. I've never caught the back end of the bed on anything like I used to with the bumper. Sucker just stuck out too much and hung down too far. I guess my theory is that the bumper is what hits stuff in the back. Without it I don't hit anything, so I don't damage the body. The 76 had dings from the bumper getting tweaked up into the bed in fact.
