We propose a torsional resonator that couples to the transverse spin dipole of an attached sample. The absence of relative motion eliminates a source of friction that would otherwise hinder nanoscale implementation. Enhanced spontaneous emission induced by the resonator relaxes the longitudinal spin dipole at a rate of ~1 s^(-1) in the low-temperature limit. With signal averaging, single-proton magnetic resonance spectroscopy appears feasible at ~10 mK and a high magnetic field, while single-shot sensitivity is practical for samples with at least tens of protons in a volume of ~5 nm^3
