Found the one I was thinking of . Flying Models issue 3/91. Note offset drive line to allow for outboard (7.5cc) laying on its side. Ran 3 chanel rudder, Throttle and Horizontal Stabiliser.
The one I remember had an outboard motor on its side and used the outboard PTO to drive cable. Narrow chord wing between the sponsons. Is this the one you're thinking of? Have the article some where.
Mike, Rick answered it in #2. Take a piece of hose to your local hose supply store and match the hose to the correct tail and get an Oeticker(spelling) Twin ear clamp.