Well, at $1699USD, no wonder.oh thats right, forgot about the quadros
The only one I can think of, is the nVidia Quadro 4800 that works in a Mac.
Check the datasheet, 2nd page, 3rd heading down.
Not exactly cheap though, as the MSRP is $1699USD.
The Mac version's data sheet didn't say one way or the other, so I checked the PC data sheet, which shows 10bit per support.That's not the Mac Edition datasheet. I read that for Mac, only 8-bit is supported.
I'll see if I can find it.There was some ranting at engadget. OSX had a limitation and I don't see any news for any Leopard.