BethpageJet thanks for that great research!
Besides 3908 (mexican AF), do you know which of your list are still JetStar -8's or -6's? i'm courious if there are still some operating.
Sadly there are roumors that 3908 is going to be retired soon and replaced by some other VIP jet, hopefully it won't be scrapped or abandoned.
As far as i know XA-PWR is still operational and based at MMTO, i took this picture in january 2011 at the FBO after it flew, the aircraft, as you say, is in excellent condition. Not the best pic quality but hope it helps.