Your quilt is just gorgeous. I am always curious to see the fabric the OBW started from, so always felt I would buy extra yardage to do a border, or part of a border. Since you don't have that, I agree with picking any of the border fabrics & you applique some big free form flowers of the colors in the quilt. Guys don't usually want feminine, flowery stuff around them, so something totally different like 9 patches, or HST's to give you a ric rac feeling to the last border would be unique & none girly. Another possibility - log cabin blocks using all the colors in the quilt would give you quite a unique border. I love the artsy look of mixing the patterns.
Oh, I do agree with the comment on keep this one the way it is & make another.