I'm guessing that you've solved the problem by now, but you make no mention of your choice of Camera Calibration. Is it set to Adobe Standard? If so, have you tried Camera Neutral?
D.
Edited: A couple of other points.......
You metion LR above, not ACR. In ACR, if you toggle between colour spaces (for those that don't know, by clicking on the blue hyperlink at the bottom of the ACR window), what you see on the screen changes to reflect this. AFAIK, this is NOT the case in LR. In LR, you are stuck with viewing your image in ProPhoto all the time. If this is the colour space you're editing to, then no worries, but if not....
This is why, IMHO, ACR is better than LR for colour criticial work. And it reminds me again of Andrew Rodney's point in an article on colour management in LR...
http://www.ppmag.com/reviews/200701_rodneycm.pdf"Here again, Adobe apparently intends to make Lightroom easy for the user by limiting the options. Time will tell if this approach is viable." I don't think it is viable.
Admittedly, this article was written before the introduction of Soft Proofing in LR4. But, if you want to use, say, Adobe 1998, having to choose between Perceptual or Relative doesn't make LR a satisfactory choice over ACR, in my view.
Rant over...