I'd look for the case being sold somewhere, even ebay/craigslist and cut out your own window.
You have some luck by contacting the vendor, they may have some spare panels lying around that they can sell you one.
Been to the site...no replacement parts...oh well like i said I have full access to a metal shop.
I work on a farm we even have a 6 foot metal lathe!...but I think the dremel tool will do nicely.
Will post pics when done