“Hybrid” transmission line circuits employing multiple interconnect levels for the propagation, or return, of a single signal line across a package length are described. In package transmission line circuit embodiments, a signal line employs co-located traces in two different interconnect levels that are electrically coupled together. In further embodiments, a reference plane is provided above, below or co-planar with at least one of the co-locate traces. In embodiments, a balanced signal line pair includes first and second co-located traces in two adjacent interconnect levels as a propagation signal line and third and fourth co-located traces in the two adjacent interconnect levels as a return signal line with a ground plane co-planar with, and/or above and/or below the two adjacent interconnect levels.