A high Z coating such as copper or gold is required on the inside of the BABAR beam pipe to contain keV range photons. This has proved to be alimit on the precision of vertexing. There are indications that therequired shielding may be a function of the azimuthal angle. The synchrotron radiation certainly is. A thinner or no high Z coating may be required on the top and bottom of the beam pipe's inner surface. If true, it should be advantageous to design a structurally thinner beampipe with fewer radiation lengths. We are working on a two layer prototype with longitudinal ribs between the layers for a coolant; and with azimuthal ribs machined into the outer layer for stiffness. It would be useful to have a finite element analysis package (e.g. ALGOR makes such a package) to see how thin a structure is possible.