Yes, Mark, you understood me correctly. Camera profiles are generally built with a set of assumptions in mind. Being pre-baked, without detailed knowledge of the photographer and his/her preferences, the scene content to be photographed, or the illumination to be used, the assumptions can only go so far. The strength of the ColorSage solution is that many of the variables are removed: information about the surface characteristics, the lighting used to capture the image, the lighting used to reproduce the image, and the characteristics of the optical system are all provided. For most general purpose photography, such detailed information is not always available, though the steps proposed by Eric Walowit (outlined by Andrew) are in the right direction.
This is one reason why most cameras provide multiple rendering presets selectable from the menu options, with names like Standard, Neutral, Natural, Vivid, Portrait, Landscape, Monochrome, Faithful, etc. Even assuming detailed scene characteristics are available, the camera designers know that photographers will simply have different individual preferences and cannot predict for a given exposure how the user will want to render that image.