I understand that a number of UK charters have had this facility installed in the past decade. As it happens - I never fly on charters! Not because of an opposition to them as such - I simply do not buy package holidays.
With regards to mainline carriers - I have never seen this. I agree that it would be dandy to watch. When carriers have the SkyMap kind of feature, showing location in graphical form - they usually turn the system off on finals, which is very annoying.
That said, I remember a flight from Geneva to London with Swiss a few years ago, when the SkyMap was on from push back. Each turn on the taxiway was shown. Amusingly, though, the graphic that represented the aircraft was pointing the wrong way by 180. This meant that Sky Map, showed us flying backwards to LHR.
