Andrew, it's an interesting story - I was familiarizing myself with the brand new 5D, and I was struggling with a cheap ball head (beginner's mistake, right?). So, I had no plans for stitching multiple photos. But the only lens I had at the time was the EF 50mm f/1.4 USM. In order to span this angle, I took four shots each in portrait orientation.
Someone was criticized on this forum the other day for posting too large of images, resulting in too long download times. Is there a generally accepted limit (ballpark) to file size?