  We study the metastable states in Ising spin models with orthogonal
interaction matrices. We focus on three realizations of this model, the random
case and two non-random cases, i.e.\ the fully-frustrated model on an infinite
dimensional hypercube and the so-called sine-model. We use the mean-field (or
{\sc tap}) equations which we derive by resuming the high-temperature expansion
of the Gibbs free energy. In some special non-random cases, we can find the
absolute minimum of the free energy. For the random case we compute the average
number of solutions to the {\sc tap} equations. We find that the
configurational entropy (or complexity) is extensive in the range
$T_{\mbox{\tiny RSB}}<T<T_{\mbox{\tiny M}}$. Finally we present an apparently
unrelated replica calculation which reproduces the analytical expression for
the total number of {\sc tap} solutions.
