Those were probably so-called "BCD" switches. You had four data lines because that's what it takes to represent all digits from 0-9, but not all 16 combinations could be dialed up, just 10. The result of putting N switches together in a control panel is a BCD number where N decimal digits are represented with N*4 binary lines.
There are a lot of surplus BCD and other types of thumbwheel switches on eBay, but I'm not sure if they're still being made these days.
