Chris - I'd think altering your line frequency would be a royal pain. When all is said and done what you're suggesting is a power regenerator, rectify your ac to dc and then invert it back to ac at a different frequency (and voltage).
Looking at my own breadmaker, its appears to be totally digital in control, and wouldn't think its timing functions depend on synchronus motors (like analog electic clocks), so your line frequency MIGHT NOT influence the control timing or functionality. Dunno. Given current economies of manufacturing, I'd think the timing would be oscillator controlled rather than based on an expensive line frequency synched synchonous electromechanical device.