You could try Perkin's Performance in Puyallup. I don't have any experience with them other than phone/email conversations, but per their website their work seems pretty solid. I have been working with them to get a rear bumper/spare tire carrier for my FJ40.
When I spoke with them a couple months ago about a front bumper for my Disco, they said they hadn't done anything for a Land Rover yet, but they would love to add that to their list. He told me the front winch bumper would run about $1200 depending on the complexity, so not sure how that would compare with a rear bumper.
http://www.perkinsperformance.com/#bumpers