Is it possible to render red / blue 3d from one image and a depth buffer?
Yes, this is essentially the same problem that occours in paralax mapping. What you basically have is a colored height field. That needs to be rendered from a second view.

There are several ways in which you can approach this. You could cheat and just shift pixels by their depth and ignore occlusion. Or you could just render a textured height map as if every pixel would be opaque. Or you could use any of the available paralax mapping methods to eliminate occlusion. 

How well this works depends on the. A scene multiple transparent surfaces wouldnt work very well without some deep map.