Unfortunately I can't give you the nitty gritty in numbers cuz I don't have any of my docs on me. I should commit all this to memory, but when you're lookign at as many products and chipsets as me, things start to get fuzzy.
Not to mention things can be configured in any number of ways depending on the OEM and their own agendas.
The 8500 can definitely do fairly high resolution on both displays. The primary can go higher though. You more than likely cannot do 2 x 2048 for instance. But you should be able to do 2048 on one desktop and 1600 on the other.
It supports mutlipe analog displays, but only 1 panel - the chip that is. If you want a card to support 2 panels you have to add another tmds controller to the board (not a big deal - again, up to an OEM or market research).
I'll see if I can update this thread while I'm at Macworld this week. Otherwise feel free to ask for all the technical bits for when I get back to work on the14th.
Bruno
Life is beautiful when you're looking at a display of 3840x2400-something and with the most vibrant colour you've ever seen.