I talked with Todd at Todd's Canopies in Florida. He makes a 20 canopy that he thinks can be adapted. The canopy is cut over size and the acrylic is flexible enough to be trimmed to fit. If you send your canopy and frame to him he will cut the canopy to fit the frame but will not install it. He has a website you can check out. I can't verify that it will work or the quality of Todd's work. If anyone has first hand knowledge please respond.
I just received a 19 canopy from someone that had sold his 19, and based on that I have some cautions. Even though it looks like it will fit, there are a couple of problems with it. First, the acrylic used is almost twice as thick so adjustments would need to be made to the frame and due to the thickness, the acrylic is not very flexible. The other problem with it is that the sides are bubbled out and don't come straight down like the original. For those reasons I'm not going to use it.
GWZ (GeeWhiz)