All arks that I have seen have the Torah scrolls stored standing vertically in the ark.
Is this an absolute halachic requirement that the Torah must be stored vertically? What if an ark contained a series of drawers such that each Torah were stored in its own drawer, or lets say one large drawer could hold several Torah scrolls, and you could store 2 or 3 laying flatly next to each other. Are there any halachic problems with storing Torah scrolls flatly?