Adjustable storage units for a vehicle and a method for providing such units are disclosed. The storage units generally include opposing end panels connected by a connecting member along the rear of the end panels. One or more shelf supports are releasably connected to the inner surface of the end panels only through apertures in the end panels. Shelves and/or drawer systems are made from polymer materials are then disposed between the end panels. The end panels may also be made of polymer materials. The storage units are adjustable or reconfigurable by removing the shelves or drawers and repositioning the shelf supports or drawer supports as desired.