ok, i popped into the mac store here in Munich and had a look myself on the new iMac ...
the overall colour gamut of the Apple iMac profile appears to be uniformly larger than sRGB by about 55% over all colours. this places it well for covering the red and blue in AdobeRBG, but doesn't come anywhere near covering the extended green in AdobeRGB.
still, there's enough gamut to make the iMac almost worth buying - and the external monitor function is another plus. the only question now remaining is how the actual measured colour profile differs from the standard Apple iMac profile ...
ragetty