1. An IC package for mounting to a surface of a device board comprising: a first IC having a first surface supporting a first plurality of conductive leads extending orthogonally from the first surface; a second IC having a second surface supporting a second plurality of conductive leads extending orthogonally from the second surface, the first and second ICs spaced apart in parallel with the first and second surfaces facing; and an interposer trace board parallel to the first and second ICs and positioned between the first and second ICs, the trace board having conducting metal traces on a non-conductive sheet material, the traces accessible from both sides of the trace board, being exposed at selected regions through the non-conductive sheet; characterized in that the conductive traces contact individual ones of the first and second pluralities of conductive leads, providing conductive signal paths from the first and second ICs between the ICs and leading to edges of the IC package.