It might be Clearview. They mention on their site that they make then to suit the rider's height. Both Clearview and Windvest seem to be some of the more popular for Rocket III owners. There are links to several in the FAQ. Link Removed
There is a company out of Florida called Fairing Screen Gustafsson / Gustafsson Plastics that makes over 3000 different windshields and screens. They make a couple for the Rocket that ar better than Clearviews in my opinion because they fit more like the original at the bottom. They make several colors also:
Clearviews Rocket 3 shield:
But Clearview has the adjustable vent that is optional and can be mounted at any height on the windshield. See here:
I have the Triumph touring screen, which I love. I keep it adjusted low enough to see over, but I still get enough wind to stay cool.
Gustaffson is a good company, when I wanted a small screen for my tiger, they had one in stock and had it to me in just a few days. They were about the only people this side of the big pond who made one for the old style tiger.