Quad Super Extended Graphics Array
Quad Super Extended Graphics Array, or QSXGA, is a video standard that defines a display resolution of 2560x2048. It uses an aspect ratio of 5:4. This is an incredibly high resolution and has no home market availablility currently (2008). However, it is used with some medical equipment to provide the best picture possible.
It's widescreen variant is WQSXGA.