The present invention stacks integrated circuits into modules that conserve board surface area. In a two-high stack or module devised in accordance with a preferred embodiment of the present invention, a pair of integrated circuits is stacked, with one integrated circuit above the other. The two integrated circuits are connected with a pair of flexible circuit structures. Each of the pair of flexible circuit structures is partially wrapped about a respective opposite lateral edge of the lower integrated circuit of the module. The flex circuit pair connects the upper and lower integrated circuits and provides a thermal and electrical path connection path between the module and its application environment. The module has a ballout pattern with a different pitch and/or supplemental module contacts devised to allow combined signaling to the integrated circuits through contacts having a desired ballout footprint. The present invention may be employed to advantage in numerous configurations and combinations of integrated circuits in modules provided for high-density memories or high capacity computing.