I spoke with Lane Wright, owner of Denver Off Road products about availablity of an aluminum brush bumper. Lane said he's been using 6061 T6 aluminum to custom build the bumpers and could likely build a PF/Frontier bumper out of 7/16" material which would be aproximately 30% stronger than 1/4" steel with about a 30% weight saving over similar ARB or Schrockworks steel bumpers. I've seen good recommendations for DOR products on other forums, and the price seemed fairly reasonable for a hand crafted bumper.
http://denver-offroad.com/index.html
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