Andrew I think your aiming at the wrong market with the rope. There just isn't a big enough demand from Rib owners because the average rib only needs a couple of short mooring lines, plus one for the anchor and perhaps a couple of long ones for locks, towing or shots for diving, as I am sure you are aware. What they are made of and by whom isn't important because you can lift most ribs with a single piece of 12mm. There is no need for expensive multi core ropes and I suspect most are bought on price and colour rather than specification. You would be better to target yachtie clubs and owner associations, for example:
However the hub flush idea does warrant merit, and could be worth joining Ribnet as a trade member. You could then do an article for the Features Section perhaps, explaining how to fit, advantages and disavantages of flushing and some photos espcially if you can show hubs that are several years old. Don't over do the sales thing, just keep it to flushing or not.