According to a http://www.sae.org/pdevent/C0108Society of Automobile Engineers:
One of the most important aspects in the design of the vehicle is in creating an interior compartment that accommodates the needs of the customer base. Occupant and interior packaginginterior packaging involves: determining the necessary amount of vehicle interior space for the customer, arranging interior and structural components in order to enhance the performance of the customer, and increasing overall satisfaction, comfort, accommodation and safety for all occupants. The occupant and interior packaginginterior packaging process relies on the sciences of human factors and ergonomics in order to design for the customer.
Tall interior packaging would be the result of raising the roof-line by lengthening or changing the angle of various structural components like pillars.