  I discuss the calculation of cross sections for processes with six and eight
fermions in the final state, contributing to single-top production and
associated top-Higgs production at a linear collider. I describe the schemes
for the treatment of finite decay widths implemented in the matrix element
generator O'Mega and give a numerical comparison for single-top production. In
the case of single top production, after reducing vector boson fusion
backgrounds by appropriate cuts, the effect of including the full six fermion
final state amounts to 2-5%. In associated top-Higgs production, non-resonant
electroweak backgrounds are of a similar magnitude while QCD backgrounds are
much larger.
