I am in the market for a new cover myself and will be going to a local canvas shop. Unfortunately the local canvas shop isn't so local however the current one was made from them in 2006 so it lasted a good life.
On my next cover I will have it basically the same as this one however I am going to add side skirts so when the boat is on the lift, the side skirts will block the sun's rays.
Another modification I want to make is adding a clear panel in the stern in order to see the trailer lights that are on the stern of the boat. While trailering these lights are turn signals and brake lights. I am not sure how the clear panel will perform when the cover gets rolled up and folded when not in use. I am still pondering that.