Try Mark Plastics in Irvine, CA. They made all the original windows and hatches for a variety of boats built in CA and are still in business. I had all the windows on my 1978 B30 replaced about 4 years ago. Called up the company and ordered the frame type and plexiglass color and they arrived about 4 weeks later in a wooden crate. Great service. They are listed on the web although I don't believe they have a web site.
