You can't change the laws of physics. Any camera requires that a lens is used to focus an image onto a surface, which means that there has to be a gap between the lens and that surface. So even very thin cameras will have a bit sticking out where the lens is. Oregon Scientific did produce their 'CardCam' model around a decade ago (which was also marketed under the 'Creative' brand name) which was only 6mm thick but it still required the lens to pop out when in use. You might be able to pick one up secondhand somewhere but it's got a very poor image resolution:
http://uk.ign.com/articles/2003/06/10/creative-cardcam-review
Nobody would bother producing such a camera these days as even the most basic cameras in mobile phones can produce better images. However, as I'm sure you're aware, photographs from mobile phones rarely come anywhere close to the image quality you can get from a proper camera. That's largely because, in an effort to keep their phones slim, manufacturers can't place the lens far enough in front of the sensor to provide accurate focussing.
Sorry!