Back in the mid 1980s, I used to work for a company that installed a lot of aftermarket accessories for car dealers. One of our most popular lines was cruise controls. We had several suppliers who may or may not still be in business. Some that still come to mind are Fridgette, ARA, and Rostra. I do remember that whoever we got the cruise controls from had electronic controls and the speed sensors was a module that installed in line with the speedometer cable. For controls they offered OEM style cruise stalks on the turn signals, clip on stalks, or a dash mounted box.
So, you could do a web search on those three companies to see if they still exist, or look in your local yellow pages for automotive accessorie to see if any one is an authorized dealer for any of the above or alternative suppliers. Might also be able to get one from a local car stereo place.
