  We introduce a novel extension of the Gutzwiller variational wavefunction
able to deal with insulators that escape any mean-field like description, as
for instance non-magnetic insulators. As an application, we study the Mott
transition from a paramagnetic metal into a non-magnetic Peierls, or
valence-bond, Mott insulator. We analyze this model by means of our Gutzwiller
wavefunction analytically in the limit of large coordination lattices, where we
find that: (1) the Mott transition is first order; (2) the Peierls gap is large
in the Mott insulator, although it is mainly contributed by the electron
repulsion; (3) singlet-superconductivity arises around the transition.
