  We consider a class of seven-dimensional N=1 supersymmetric orbifold GUTs in
which the Standard Model (SM) gauge couplings and one of the Yukawa couplings
(top quark, bottom quark or tau lepton) are unified, without low energy
supersymmetry, at M_{GUT} \simeq 4 \times 10^{16} GeV. With gauge-top quark
Yukawa coupling unification the SM Higgs boson mass is estimated to be 135 \pm
6 GeV, which increases to 144 \pm 4 GeV for gauge-bottom quark (or gauge-tau
lepton) Yukawa coupling unification.
