What's the power draw of your clock? 50Hz is within the range of most LFO circuits (Low Frequency Oscillators) of the kind used for modular synthesisers and guitar effect pedals. You could combine one of those circuits with a simple voltage follower (consisting of a power op-amp or BJT transistor plus a couple of resisters) to keep the frequency at a stable 50Hz under load, and finally a transformer to convert the signal up to 110V.

All in all, I would estimate that this could be done with a single IC providing a few op-amps, a handful of passive components and a transformer; probably under US$30 or $50 with a nice case and plug.