These are the good replacements
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?t=22282&highlight=rock+lizard+rear+bumper
although it's 110 lbs of steel and you have to paint it yourself.....
To get the stock rear off - wasn't too difficult - I think 3 sheet metal screws in the center top, 6 pop rivets 3 on each side - 2 screws on each side (hard to get to - under the fender lip) - I also had to drill out 4 rivets - but they were holding on the crush cans in the center - if you're just doing the bumper it's not neccessary.
To buy a new bumper - you're probably looking at a dealer - you might try Ebay (although if you get it off - you might be able to pop it out from the inside)
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2005 CRD
stuffSkeptic quod gratis asseritur, gratis negatur