I got a tip about a new piece of software called ‘Gimpel3D’ that offers 2D/3D conversion.  From their description:

Gimpel3D converts single images or frame sequences into stereoscopic 3D using a combination of traditional approaches and a proprietary projective modeling system.

The user works in true proportional space where the scene can be viewed from any location. The scene is edited geometrically in space using tools specifically designed to work with the perspective projection of the image.

It looks pretty powerful, as evidenced from some of the demonstration videos available on their site (I’ve embedded one below).  

It’s available free in a “shareware” version that watermarks images and maxes out at 720×480, but is available for only $200 for a single-seat license. I also have it on good authority that the developer is available for custom integration work 🙂

via Gimpel3D – Stereo 2D/3D Conversion Software.