  Grand-unified models with extra dimensions at the GUT scale will typically
contain exotic states with Standard Model charges and GUT-scale masses. They
can act as messengers for gauge-mediated supersymmetry breaking. If the number
of messengers is sizeable, soft terms for the visible sector fields will be
predominantly generated by gauge mediation, while gravity mediation can induce
a small mu parameter. We illustrate this hybrid mediation pattern with two
examples, in which the superpartner spectrum contains light and near-degenerate
higgsinos with masses below 200 GeV. The typical masses of all other
superpartners are much larger, from at least 500 GeV up to several TeV. The
lightest superparticle is the gravitino, which may be the dominant component of
dark matter.
