I would like to see the plans as well! My current plastic greenhouse has been at it's life's end for a couple of years now. I'm always amazed when it makes it through another winter without collapsing. I go inside after a snowfall and use an industrial type broom to push up on the sagging plastic and bounce the snow off. One of these times I'll probably be buried under an avalanche.
Past time for a new structure, but once I'm through the seedling stage I don't use it, so keep putting off plans for a new one for one more year.