A seating system includes a load bearing shelf which is provided for carrying seats, cargo and the like. The shelf is slideably supported on opposite ends in spaced, parallel, horizontally extending tracks mounted longitudinally in the vehicle. Seats may be removably and lockably mounted to the shelf which, upon removal, allows use of the shelf for storage and other functions. The shelf is removable, and may be reversibly reinstalled in a front-to-rear reversed orientation and locked into various positions. Further, the shelf may include upper and lower convenience structural features such as pockets, sliding trays, and compartments.