I was looking for a table cover as well. friend of mine told me about a local plastics company that could make anything. They cut and fabricated a perfectly fitting cover for a fraction of what I could find online.
I'd do a search locally for companies that work with plastics my bet is you can get a better made and better fitting custom cover made locally. Of course what local is to you may change this, but if your close to a city they should have a company that can fab a cover for you.