Stacked semiconductor devices and assemblies including attached lead frames are disclosed herein. One embodiment of a method of manufacturing a semiconductor assembly includes forming a plurality of first side trenches to a first intermediate depth in a molded portion of a molded wafer having a plurality of dies arranged in rows and columns. The method also includes forming a plurality of lateral contacts at sidewall portions of the trenches and electrically connecting first side bond-sites of the dies with corresponding lateral contacts of the trenches. The method further includes forming a plurality of second side channels to a second intermediate depth in the molded portion such that the channels intersect the trenches. The method also includes singulating and stacking the first and second dies with the channels associated with the first die aligned with channels associated with the second die. The method further includes attaching a lead frame to the lateral contacts of the stacked first and second dies.