I used 28 count Charles Craft Monaco fabric in Antique White, and the finished pattern measures 9"x 18". The frame is a little taller than I'd like, but I used one I already had. I may eventually get one custom made so it more resembles the one from the movie.
In 2007, I had the opportunity to tour Ohio State Reformatory in Mansfield, Ohio, where Shawshank was filmed. It was really a wonderful tour and I highly recommend it. I'm thinking of making another needlepoint and sending it to them for display in their museum. You can check out the pictures I took on my tour at my Flickr site.