Haven't added one yet but I am going to! I was looking at this basket I found on ebay the guy said he can custom make one to your size you just take the measurements. He also told me that he can fabricate the mounting bracket because I don't have the roof bars either. I haven't ask him if he could make it out of round tubing because his are square in the pics. But they are supper strong. Check it out
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewIte...ame=STRK%3AMEWA%3AIT
He quoted me a price of $535.00 + sh. My measurements were for a basket 90" x 48" and that covered the roof. He also said he would install light mount on the basket.