They left for a few years, however not only do they make an onroad engine they make a complete onroad vocational class 8 truck:
http://drivecat.com/engines
http://drivecat.com/overview
Mind you , not that any of these are pick-up engines with CAT, but wanted to point out they are still in the onroad applications. One of the biggest problems for CAT was most heavy duty truck manufacturers now a days make their own engines and will only sell their own engines with their trucks and it left CAT with out a market to have their engines available in, their fix is now their own truck.