Although Microsoft is keeping mum on when Windows Phone 7.8 will arrive, it seems that the day is getting closer. Recently, more people are posting pictures or video on WP7.8. Here is a video showing Windows Phone 7.8 on Nokia Lumia 510.
Although in the settings of the phone is in Chinese, you can still see the changeable Tile size. At this moment, there is no official information on what to expect on Windows Phone 7.8. The only significant thing is the adjustable Tile. Check out the video.