I was waiting to see if anyone else knew what brand it was, cause it sure don't look familiar to me. Is it plastic or glass? It has a mount for a motor on it also? Hank paddles a pontoon by Kiwi, maybe it may ring a bell with him. They also have different watercraft up in Canada than we have here also, maybe it's a foreign job that got brought here. If it's glass, I would guess someones garage or small shop, if it was rotomolded out of plastic, probably a larger company made them because of the cost of the molds.
For not being answered, you asked something most people wouldn't know about unless they had seen one for some reason. There just isn't that many pontoons being used today like the one you have. My answer didn't help much but it's all I have to offer, sorry.
Perry