Google may soon be rolling out an actually exciting tablet prototype that would give the devices the ability to capture images (presumably both moving and still) in 3D.

The Wall Street Journal reports tonight that people familiar with the matter say there are around 4,000 of these prototype units being produced. The sources further claim these seven-inch tablets will feature two rear cameras as well as infrared depth sensors.

Anyone know of a place where one might find around 4,000-ish Android developers to build apps for such devices? Google I/O, perhaps? Something to ponder, especially since Google has a habit of throwing around early prototypes at the annual developer event.

Also possibly relevant: Project Tango, Google’s bid to bring 3D mapping to phones and other devices.

“We are physical beings that live in a 3D world,” wrote Google’s Johnny Lee, the head of the Tango Project team, in a blog post during Tango’s announcement. “Yet our mobile devices assume that physical world ends at the boundaries of the screen. The goal of Project Tango is to give mobile devices a human-scale understanding of space and motion.”