The largest gigapixel photograph ever created with a DSLR camera was made by A.F.B. Media GmbH in Dresden, Germany. 1655 images, each 21.6 megapixels in size, were taken with a Canon 5D Mark II and a 400 mm lens over a period of 176 minutes. The images were stitched on a 16 processor system with 48GB of main memory, taking 94 hours to create the final result.
See it here.