After a fashion, they are still in business - now known as Aeroliner boats. Website: aeroliner-boats.com. Some pretty good historical stuff on the site, too. I haven't dealt with them, but they seem pretty knowledgeable about the older stuff...
Speedliner mahogany boats were made by General Marine, St. Joseph Mo. out of production for quite a while. My 15' is 1960 year model. They apparently measured around the gunnell as mine is listed as a 16' but centerline is 15'
