In a major merger, two supermassive black holes may meet at the center of the merger remnant. Before their eventual coalescence, the giant black hole pair endures prolonged interaction with its environment, which may produce electromagnetic emissions. If observed, these would represent direct probes of late-stage merger dynamics, and could provide a smoking gun for gravitational wave emitters detectable by "Pulsar Timing Arrays". No small-orbit binary systems have yet been conclusively confirmed. We are investigating the use of both electromagnetic observations and Pulsar Timing Arrays to constrain, support, or disprove the binary SMBH hypothesis in candidate systems. We will present results from ongoing searches for binary supermassive black holes, and will consider the near-term prospects of Pulsar Timing Arrays to place physically interesting gravitational wave limits on these and other nearby targets.