There are still some XBs going around, but unless they have been rebuilt they would be getting very old by now. I used to own a 1978 XC, which had done around 900,000km before I finally got rid of it.
In Sydney I have seen somebody driving around in one of the yellow Falcons (see last picture in above link). I doubt it was real.
There is a company in the US that is importing XB GT Coupes from Australia. I don't think they were cheap once they come across, but I guess you end up with a unique car, with readily available engine parts.