My chipped adapters used for my Zeiss lenses actually front focus. Rather, it's me doing the front focusing, but based on when the adapter "tells" me focus is achieved. I've just ordered a new type of chip which, according to the manufacturer, allows micro adjustment of the focus confirmation. In the lens, I should add. Not in the camera body, like the more expensive EOS-cameras. Can't wait to get the adapter and try it out. Furthermore, the new chip tells the camera that an AF lens is attached, all my current adapters tell the camera that a MF lens is attached (which of course is the case). The benefit of "fooling" the camera into thinking it has an AF lens attached is, supposedly, that you can not take a picture until at least one AF-point is in focus, even if you press the shutter button fully. This should help in shooting moving objects; simply press the shutter button fully while pointing towards the subject, turn the focusing ring and the photo is taken as soon as focus is achieved, not sooner.
At least that's what the manufacturer claims, I will hopefully know in a couple of days...