PhoneArena has obtained an image of something that definitely looks like it could be a white Nexus 4. Here's the photo in question.
The quality isn't fantastic, but what we're looking at does appear to be a Nexus 4 that's been through a serious bleaching. The reflective pores are still present (see the bottom-right of the photo), and the camera module now appears to have a slightly visible border. This may just be a result of the fact that the white color shows the outline more clearly.