Dayglow --
Perhaps you've come to this realization(or not) already, but one way to at least partially achieve your goal could be looking for powercords based on solid-core wires, believing them in general to entail many, if not all of your sought-after qualities to "improve clarity in complex passages, add bass slam/definition and create a more open/liquid presentation without giving up speed-resolution and neutrality ..." Where I've tried solid-core powercords in my setup - in different configurations and wire diameter, etc. - in all cases they've provided a more calm, liquid, and resolved sound. Bass seems notably more tight and yet weightier, subjetively deeper, and more aperiodic. Mids appear more physical, relaxed, and a "shouty" and thinnish tedency has been eradicated(at least over my speakers and compared to the different multi-strand alternatives I've tried); highs are more finely structured and not least more clean sounding. Overall the immediate sonic impression of these qualities reveals a slightly varmer, more full and relaxed sound.
Is your system (star-)grounded? Grounding my system, especially my poweramp(NuForce Stereo 8.5V3), lead in particular to a better bass respons - much like above impressions of the solid-core powercords.
Oh, I'd also pay attention to the powercord(if you haven't already) from the wall outlet to your powerstrip/-distributor. Using solidcore-based wires here has a definate, and positive effect in the same vein as well.