In response to my question in the Adobe Photoshop Forum, Jeff Schewe, the well known guru, replied that in Photoshop CS6 CC you can add arbitrary RGB profiles to the Workflow Options in ACR. Workflow Options opens when you click on the blue description of the profile you are opening the RAW file with, at the bottom of the ACR window.
Does anyone know any other RAW file converter that has this option? I have just asked ACDSee tech support about this. It is not apparent that they have this capability in the Mac version. I'm haven't looked thoroughly at any of the others I have yet. You would think that draw or converters based on it would be able to do, this such as GIMP or RAWTherapee.
I have a bunch of iccs I'd like to add, like MaxRGB, PhotoGamut, ECI.
I was able to add iccs to Photoshop 5.1 to use for conversion after opening by going to Library/Application Support/Adobe/Color/Profiles, but I don't see even that capability for ACDSee.