1. An interposer for use in a semiconductor device assembly or package, comprising: a substantially planar interposer substrate; at least one attach region on a surface of said interposer substrate; a plurality of first contact pads proximate to said at least one attach region; a plurality of second contact pads carried by said interposer substrate, each second contact pad corresponding to a first contact pad of said plurality of contact pads and electrically connected thereto by a conductive trace extending therebetween; and a plurality of receptacles formed at least partially through said interposer substrate, at least some second contacts of said plurality of second contacts at least partially exposed by a corresponding receptacle of said plurality of receptacles.