So far it appears that lot number 0842 from team FDOU or CSON and 0843 FDOU have been confirmed Jasper. Unfortunately, the somewhat confusing bit is that some of these same lot numbers have also been confirmed to be Falcon. Clearly, we are in the midst of a transition period, so there are still no guarantees based on external box markings. If you get a console labeled 12.1A on the 12V rail and comes with a 150W PSU, you can be assured that you have a Jasper-based console.
I would like to reiterate that Microsoft will likely never comment officially on Jasper or any other Xbox 360 revision, so don't waste your time trying to contact them. Along the same lines, your average retail employee is not going to have a clue what you're talking about if you ask, so don't bother.
