Apple does advertise support because they were the ones who added the support in their OpenGL drivers.
Where?
I have looked.
Look, I'm not saying that it's impossible - or even that 10-bit color is definitively unsupported.
I'm more getting at the fact that it's half-baked right now. I've yet to see anything written by a website or journal I trust on the subject, and everything I've read so far says it isn't quite there yet, though all the technical issues have been solved.
I find it also relevant to point out that AMD's documentation says that "Adobe does not provide support for 10-bit image display for Adobe Photoshop CS5". This is likely because support is not yet at the point where any company will stake its reputation on it, and also because Display Port uptake isn't high enough (later revisions of HDMI do provide enough bandwidth, but it's not a popular port in the pro space).
For all I know, it's three terminal commands away, but all evidence and web searching says that this isn't ready for primetime.
By all means, please let us know what you find when you guys get it going on your end, or get some of the professionals you know to write an article, or post something.
I would like to know, but everything I've seen so far is a lot less definitive than such a subject should be.