As others have said, Man-a-fre in SoCal has a few Kaymar bumpers in stock for the LR3 (or soon will, they were in shipping not long ago). Safari Guard came out with one, but the owner was reactivated and is currently serving his country overseas, so they are not available presently. Rovetyme developed a two piece rear bumper, not sure if they ever actually released it, but they might if you asked.
The Kaymar is by far the most professionally looking one, but it does not provide much if any advantage, it is exactly the same profile as the OEM plastic bumper. The Rasta tire carrier is pretty good. No rattles, even on washboard.
There is another company in Australia making a tire carrier, I forget the name, but look up Simon on Disco3.co.uk and you'll find him.