HDMI 2.0 is supposedly able to stream 4K at 60fps (and 32 audio channels along) with only 18Gbps. That's something close to 2.5 GB/s, but let's round up to 3GB/s to make things harder.

PCI-Express 2.0 (what all modern GPU are compatible with [heck, some say they can use PCI-E 3.0, which is almost twice as fast]) boasts 500 MB/s per channel. So a x16 port (like most use), gives us 8 GB/s, give or take a few dozen MB/s. Much higher than the 3 GB/s from the first article and, in fact, more than twice that, so 3D is possible.

Now, monitors? I'm sure there are already some pretty badass 4K monitors out there, so I'm sure it can happen.

The big question, however, is why the hell would you do it?!