The way out of gamut paintings are typically oils on canvas, and are often glazed.
I haven't tried any of the papers you mentioned. Do you know if any of those are similar to Breathing Color's Vibrance Rag (Baryta photo gloss) - which I have tried? Sounds like some of them may be similar. I haven't tried putting a Vibrance Rag print in front of these artists, figuring they wouldn't think of it much different than RC gloss paper, but perhaps I should give that one a shot. I'll take a look into all the papers you mentioned - thank you very much!
Vibrance Rag does not have a true clone as far as I can judge. PIctorico GKR is close though but a lower weight, texture is more pronounced in GKR. HM Photorag Satin is less close on the white, is smoother and more matte. The paper whiteness is almost like IGFS, Canson Rag Photpgraphique Innova IFA69, but the rag base contains a bit more OBA.
Met vriendelijke groet, Ernsthttp://www.pigment-print.com/spectralplots/spectrumviz_1.htm
400+ inkjet paper white spectral plots, October 2012:
NEW added: Tetenal-Mitsubishi, NEW halfway: Kodak-Bonjet,
NEW to do: Permajet-FelixSchoeller-Sihl
Would like to get samples: InkPress-JonCone