I bought glass to replace the end panel on a 55 Gal a few months ago from a local glass shop in Kirkwood. At that time I asked about cutting some glass I had on hand (broken back to a 55 Gal). If I remember correctly, they told me it would be $10 a cut. Of course that is for a sheet, not an assembled tank. If its even possible to do, I seriously doubt they would do it for with any kind of guarrentee.