Microelectronic devices and methods for manufacturing such devices are disclosed herein. In one embodiment, a packaged microelectronic device can include an interposer substrate with a plurality of interposer contacts. A microelectronic die is attached and electrically coupled to the interposer substrate. The device further includes a casing covering the die and at least a portion of the interposer substrate. A plurality of electrically conductive through-casing interconnects are in contact with and projecting from corresponding interposer contacts at a first side of the interposer substrate. The through-casing interconnects extend through the thickness of the casing to a terminus at the top of the casing. The through-casing interconnects comprise a plurality of filaments attached to and projecting away from the interposer contacts in a direction generally normal to the first side of the interposer substrate.