I remember they were promoted in the Hobie Hotline. Probably about 1973. There was definately a Colman connection since VW did a "Coleman Special" at about the same time.

I expect that the Hobie version was simply a dealer installed "tape packge", with the roof rack and sailboard added to whatever was in stock.

I have seen these listed on E-bay several times.

http://www.thesamba.com/vw/archives/postcards/hobiecatvanagon_a.jpg

http://www.thesamba.com/vw/archives/postcards/camper_colemanpkg_b.jpg

http://www.thesamba.com/vw/archives/postcards/camper_colemanpkg_a.jpg