Contact assemblies for electrochemical processing of microelectronic workpieces. The contact assembly (400) can comprise a support member (410) that includes an inner wall (412) which defines an opening (414) configured to receive the workpiece and a plurality of contacts (420). The individual contacts (420) include a conductor (440) and a cover (430). The conductor (440) can comprise a proximal section (435) projecting inwardly into the opening (414) relative to the support member (410), a distal section (436) extending from the proximal section (435), and an inert exterior (444) at least at the distal section (436). The cover (430) comprises a dielectric element that covers at least the proximal section of the conductor, but does not cover at least a portion of the distal section of the core. The exposed portion of the distal section of the core, accordingly, defines a conductive contact site for contacting a conductive layer (e.g., a seed layer) on the workpiece.