I know there are video cards that display True Color (24 bit color), but are there any video cards that display Deep Color (30, 36 and 48 bit color)?
Further-more are there any display devices that can handle Deep Color?
The ATI FireGL™ 3D Workstation Graphics Accelerators support 16-bit per RGB channel (48-bit color). "Beyond true color" video is typically used for HDRI applications (high dynamic range imaging).
Microsoft announced that color depths of 30-bit and 48-bit would be supported in Windows 7 if you have a video card that supports 48-bit color and a monitor that supports 48-bit color using hdmi 1.3.
Here are a few articles I found about monitors supporting HDR and 48-bit images:
Your eyes can certainly recognize much more colors than 32bit depth allows to display. If you look closely you can clearly see the line separating colors in various gradients, like the one mentioned above. 48-bit color depth is very useful if you're working with 48-bit images, which will make your gradients, fades etc much smoother, if you find a printing service that is capable of printing it.
The color depth is one of the reasons why analog photography can still be superior to digital photography, the other one is the resolution, because in analog photography there is no "pixels".
The low fps (films are still mostly in 24 fps, games usually are capped at 30 or 60, while eye can recognize much more, and many First Person Shooter players state that being able to see 200 frames per second makes a huge difference) and low color depth being a standard, shows just how much space for improvement and progress there is.