prepanel.lmline(x, y, ...)
prepanel.loess(x, y, span = 2/3, iter = 3, ...)
prepanel.qqmathline(x, distribution, ...)xlim, ylim, dx, dy, the first
  two being used to calculate panel axes limits, the last two for
  banking computations.lowess, trellis.par.get,
  Lattice