I don't know much about prepress color management, although I do know a bit about photo color management. For photo purposes, an RGB driver that doesn't apply sharpening is usually color manageable by profiling. Here the printer guys have already done the hard part of bringing 12 or so variables (ink intensities) down to 3. The problem from the user side is usually finding the tricks to get the right amount of ink onto the media type being used, and thereby ensuring both a sufficient gamut and no excessive overinking. Once a profile has been computed it will be applied on the application side. I am sure there are good reasons why people want to have color management in the print channel. I assume the central motivation is that this allows printing to a remote machine without storing profiles locally. I'd say this is a less than perfect workflow, though, because if you don't have local copies of your profiles you cannot do softprooofing. I think having a documented place to put profiles, an utility to do profile conversions -applying a printer profile to a Tiff file already in a standard space like sRGB- and well documented inking options for deliberately uncorrected workflows in the printer driver per se, would allow photo printing to proceed very well with the current generation of open source print drivers like CUPS and Gutenprint. No major engineering required, folks, the heavy lifting has already been done. Edmund