In addition to the body of evidence reviewed here, studies of satellite dynamics from SDSS data indicate large M / L ~ 100 - 200 at radii 260 h-1 kpc in 0.5 - 3L* galaxies, and gravitational lensing studies indicate nearly isothermal mass profiles (constant CVCs) with a modest dark matter fraction inside 2Re [e.g., 45]. Space did not permit a detailed discussion of these issues here.
Alltogether the case is strong that, like all galaxies, elliptical galaxies have dark matter halos surrounding them, with most inner circular velocity curves nearly flat. But there may be some intermediate luminosity objects in which the halos are more diffuse. Future work to understand this is clearly worthwhile.