Being lazy by asking rather than investigating this myself, but I do have a ColorRight WB tool, which works like a gray card for setting custom WB except you place it over your lens and take a shot, and it hashes the incoming light to 18% gray. It's been gathering dust since I started shooting RAW and just adjusting WB in post. My question is, if you set a Custom WB in-camera, shoot RAW, and open that RAW file in a 3rd party converter (DxO, LR3, etc.), will that 3rd party converter use the custom WB? I'm guessing the answer is yes, since they use what's stored by Auto as the shot settings, but confirmation would be nice.

Yesterday, I was shooting in a courtroom with horrible mixed lighting. Fortunately, being a courtroom there was white paper laying around that served for a WB reference in post. But I might bust out the ColorRight again and try custom WB for RAW shooting - in some settings, that might give better results than guessing in post.