I was given the following reprint at Dinofest by one of the authors:
M. van Tuinen, C.G. Sibley, and S.B. Hedges. 1998. Phylogeny and
biogeography of ratite birds inferred from DNA sequences of the
mitochondrial ribosomal genes. Mol. Biol. Evol. 15: 370-376.
I haven't read the paper carefully yet, but it sure looks interesting.