  We consider a gauge extension of the electroweak sector of the Standard Model
based on the group G_2 x SU(2)x U(1). The exceptional group G_2 is the smallest
rank two group that contains SU(3) as a subgroup; the SU(3) prediction sin^2
theta_w=1/4 follows approximately in this model if the couplings of the
additional SU(2) and U(1) factors are sufficiently large. We study the symmetry
breaking sector of the model, the bounds from precision electroweak constraints
and the mass spectrum of exotic gauge bosons that may be produced at future
colliders. We also discuss an SU(3) electroweak model in which a vector-like
sector is included explicitly to facilitate the decays of otherwise stable
exotic states. The models considered here represent plausible extensions of the
minimal SU(3) electroweak model with potentially distinctive TeV-scale
phenomenology.
