I have a 1997 1440 Flatbottom.
I built my frame out of 3/4" EMT and Bimini Hardware. It was pretty easy. Somewhere down the page there is a Montana Redneck Boat Blind or something like that. I couldn't make that work without the frame hanging over on my boat. I hunt in timber a lot, never going to happen. My boat has an angle up front and I wanted to have that framed for the blind just to simplify my life.
My original one looked similar to this
I left out the third extension
Thought it would be cool to change it so I had a roof so I modified it to look like this. http://www.mudbuddy.com/Quick%20Flip%20Deluxe.htm
Hated it. Couldn't see birds above me or behind me. Had to give up working ducks if they flew that way.
Went back to the frame with extensions and made the angle of the where the frame meets higher. Now if I want it closed it will fit without me hitting my head on the material but I am still able to see behind me and above me.
Total cost of frame, hardware, and material. Appx 75 bucks.