Inertial electrostatic confinement (IEC) of a non-Maxwellian beam-dominated plasma for fusion was originally proposed in the 1950s, but since then, only sporadic work has been devoted to the subject. Nevertheless, recent experiments have shown that small IEC devices are well-suited for commercial applications as a portable low-level neutron source for activation analysis. However, the scaling to a high-power fusion reactor is uncertain, due to the lack of experimental data with higher input currents. Three key issues need to be resolved: the stability of multiple-potential-well structures, the confinement time of energetic ions trapped in such wells, and the protection of grid structures during high-power operation. Conceptual design studies that assume a positive resolution of these issues show, however, that the resulting reactor would be economically attractive and very versatile.