From computerandvideogames.com:

Experiments within Sony’s R&D department are thought to have been extensive. Versions of the new PS4 pad include biometric sensors on the grips and an LCD touch screen, the development source claimed.

A second source, working in a separate part of the industry but still connected to Sony, said PlayStation engineers are “trying to emulate the same user interface philosophies as the PS Vita”. This is likely a reference to the touch-screen capabilities of the PlayStation handheld, and a suggestion that Sony will tightly integrate its portable and home systems.

The new console – codenamed Orbis – will be revealed in a matter of weeks, not months.

For every product or idea that reaches a finished product, there are dozens that don’t. It should be pretty obvious, that there are probably thousands of wacky PS4 ideas and experiments inside of Sony that get cut. Knowing the video games news cycle types, people can take scraps of information from an internal brainstorm and over read into that and extrapolate that into the final direction of the PS4.

The known I/O paradigms are:

• Traditional sticks/buttons and a living room type standing TV setup
• An all-in-one tablet device that doesn’t need an external TV
• A Wii U type tablet/TV hybrid scheme
• A TV + motion wand like the Wii or PlayStation Move
• A TV + controller free motion detector like the Kinect
• VR headset like the prototypes from Oculus Rift

Out of all of these, I would take the safe bet that Sony takes the safe bet with a PS3-style control scheme with some clever enhancements. My personal hope is that Sony is building a gaming platform entirely around VR. The Oculus Rift team is currently the leader of publically demoed prototypes. The big downside to the Oculus Rift is that it’s an add-on peripheral and doesn’t seem like it will attract a lot of my favorite development studios: Rockstar, Atlus, From Software, Insomniac Games, and all the Sony first party teams. I’m hoping that Sony’s big PlayStation reveal will be VR hardware and a VR platform but that seems a long shot right now with no rumors or leaks pointing in this direction.

However, I’d bet against a Wii U type touchscreen controller or a biometric sensor controller being a flagship controller for the PS4. Neither of these concepts fits PlayStation’s games at all.