I've did exactly like you described and I think I got quite good result. I've created calibration matrix from manufacturers profile and measurements of my monitor that was set to match profile's requirements (G2.2 D65). Difference between white points with and without correction is 15dE, so it's huge.
Hmm. I wonder if that's a hint that the absolute white point isn't being restored properly for one of the profiles ? Graeme Gill.