Recently we got a job where our customer wanted the job to be unique in terms of printing quality.
Usually we follow FOGRA 39 standards and use GMG color server to convert the incoming profiles.
The customer gave us PDF files with images converted US Web coated SWOP icc profile.
We extracted images from PDF into Photoshop. We created a new icc profile with more separations on CMY and with skeleton black (using Under color addition UCA which is opposite way to GCR)
We then converted images in photoshop first to sRGB and then to target profile using absolute calorimetric indent. The plate curve and press settings as per ISO 12647-2.
You don't believe, results are so superb and customer was really excited with results saying it matched with his original art work in design stage and RGB mode.
We are also pleasantly surprised with the results.
May be this is useful for you. Please comment