There has been no official word of the UKPK being discontinued. I hope it stays around for a long time. I have one and carry it everyday.
Sal gave confirmation, awhile back, that a more affordable UKPK would be released. It is called the United States Pen Knife (USPK). It will feature FRN scales and GIN-1 steel. I believe it will also have a wire clip but I'm not positive on that. Essentially, Sal wants to provide a more affordable option for those in restrictive locations. They can legally carry a well-made knife, with excellent ergonomics and not hurt their wallet too much.
I've never had a knife with GIN-1 steel but I know there are fellow afi's who have. From what I've gathered, it has good corrosion resistance and is from Japan. I think it's a notch under VG-10 but is superior to 8cr13mov.