  We propose a realistic flipped SU(5) model derived from a five-dimensional
orbifold SO(10) model. The Standard Model (SM) fermion masses and mixings are
explained by combining the traditional Froggatt-Nielsen mechanism with the
five-dimensional wave function profiles of the SM fermions. Employing
tree-level spontaneous R-symmetry breaking in the hidden sector and
extra(ordinary) gauge mediation, we obtain realistic supersymmetry breaking
soft mass terms with non-vanishing gaugino masses. Including the messenger
fields at the intermediate scale and Kaluza-Klein states at the
compactification scale, we study gauge coupling unification. We show that the
SO(10) unified gauge coupling is very strong and the unification scale can be
much higher than the compactification scale. We briefly discuss proton decay as
well.
