I just tried images for overscan and I see none at all on my computer monitor. The PS3 is putting out the whole image. If people have overscan issues, it's likely the TV. There is overscan when setting the PS3 to 720p, but that's the monitor's fault and I already knew that.
I certainly would like some overscan adjustment. The way it is now, the monitor stretches 1080p material vertically to fit the (16:10) screen. For some reason, 720p is only stretched very little and cropped on the sides, which I strongly prefer to the noticeable stretching of 1080p. If they could have a setting to adjust horizontal and vertical separately, I could compensate for the monitor's stretching. That would really be nice.