  We investigate the statistical evolution of magnetic neutron stars, recycled
in binary systems, simulating synthetic populations. To bracket uncertainties,
we consider a soft (FP) and a stiff (PS) equation of state (EoS) for nuclear
matter and explore the hypothesis that the magnetic field is confined in the
stellar crust. We follow the magneto-rotational evolution within a simple
recycling scenario, including the possibility of magnetospheric propeller.
  We find the presence of a tail in the period distribution of the synthetic
populations at periods shorter than 1.558 ms, the minimum detected so far. For
the soft EoS the recycling gives rise to a spin distribution which is
increasing monotonically toward short periods and a clear ``barrier'' forms at
the minimum period for the onset of mass shedding. For the stiff EoS the
distribution is flatter displaying a broad maximum about 2-4 ms.
  The estimated fraction of neutron stars spinning close to their shedding
limit over the millisecond pulsar population is found to be significant.
Crustal magnetic field decay models predict the existence of massive (M>1.4
M_sun) rapidly spinning neutron stars with very low magnetic moment.
