The so-called March model of fullerene, in which a self-consistent spherical distribution of pi electrons is combined with the proper nuclear-nuclear potential energy for the correct structure, is here extended to boron cages. The Thomas-Fermi approximation of the initial studies is here replaced by Hartree-Fock calculations. Explicit results for B-2k and B-2k+1(+), with k ranging from 15 to 27, are discussed and compared with calculations on similar clusters found in the literature.