I've struggled with research myself to no avail. If you discover who supplied the ports please pass it on. I have replaced a few fixed with lexan and new gaskets from my window contractor as the ericson used unique sizes
I ended up buying some ports from Beckson Marine. For the sailing I do they are fine and considerably less expensive than Lewmar. Certainly not in the same class, but acceptible for coastal crusing. I found nothing to be an exact match
I replaced the opening ports in my E-36 from Atkins and Hoyle in Canada. They had ports that were almost a perfect fit in the holes from the original equipment. http://www.atkinshoyle.com/
Just today, while looking for another product, I found that Taylor Made has a line of opening ports.
In case this might be new news to anyone else looking for alternatives, here is their URL -- http://www.taylormarine.com/portlights/index.html