  We construct two new classes of models for double beta decay, each of which
leads to an electron spectrum which differs from the decays which are usually
considered. One of the classes has a spectrum which has not been considered to
date, and which is softer than the usual two-neutrino decay of the Standard
Model. We construct illustrative models to show how other phenomenological
bounds can be accommodated. We typically find that, although all other bounds
can be satisfied, the predicted double-beta decay rate only in one class of
these models is at best large enough to be just detectable in current
experiments.
