There have been a few manufacturers of apaches around the 56/58" length over the years. I cannot say I remember seeing any with that deck layout though. As you mention - the squared rise to the hatch is certainly distinctive. It almost appears that it was fabricated from wood or similar as it has very little rounded shape to it. The hatch looks more like those of Aeromarine etc. Be curious if it was not an early prototype or similar. That said - the chances of finding another are unenviable. I could see modifying an existing hatch but not sure I see the need - the pointed slope of Aeromarines and similar is not a bad look. Though worth noting that Aeromarine do not appear to be producing hulls. There are a few other options though