  Several recent observations suggest that gas-poor (dissipationless) mergers
of elliptical galaxies contribute significantly to the build-up of the massive
end of the red sequence. We perform a series of major merger simulations to
investigate the spatial and velocity structure of the remnants of such mergers.
Regardless of orbital energy or angular momentum, we find that the stellar
remnants lie on the fundamental plane defined by their progenitors, a result of
virial equilibrium with a small tilt due to an increasing central dark matter
fraction. However, the locations of merger remnants in the projections of the
fundamental plane -- the Faber-Jackson and R_e-M_* relations -- depend strongly
on the merger orbit, and the relations steepen significantly from the canonical
scalings (L sigma^4 and R_e M_*^0.6) for mergers on radial orbits. Our results
imply that the projections of the fundamental plane -- but not necessarily the
plane itself -- provide a powerful way of investigating the assembly history of
massive elliptical galaxies, including the brightest cluster galaxies at or
near the centers of galaxy clusters. We argue that most massive ellipticals are
formed by anisotropic merging and that their fundamental plane projections
should thus differ noticeably from those of lower mass ellipticals even though
they should lie on the same fundamental plane. Current observations are
consistent with this conclusion. The steepening in the L-sigma relation for
luminous ellipticals may also be reflected in a corresponding steepening in the
M_BH-sigma relation for massive black holes.
