Microelectronic devices, microfeature workpieces, and methods of forming and stacking the microelectronic devices and the microfeature workpieces. In one embodiment, a microfeature workpiece includes a plurality of first microelectronic dies. The individual first dies have an integrated circuit, a plurality of pads electrically coupled to the integrated circuit, and a plurality of first conductive mating structures at least proximate to corresponding pads. The first conductive mating structures project away from the first dies and are configured to interconnect with corresponding complementary second conductive mating structures on second dies which are to be mounted to corresponding first dies.