I converted one of my trailers to bunks. I am not one to re-invent the wheel, so I went to Chinook Landing with my digital camera and took pictures of trailers like mine with bunks. Mainly the parts and connections that I would need to purchase. Then I got the parts from WestMarine Supply, Fishermans, and some mail order, like...
http://shop.easternmarine.com/index....categoryID=223
The problem with mail order is the shipping cost is high. Hope this helps.