Dell ran its entire business on the Objective-C version of WebObjects (4.5) for quite some time, until about 2000, if I recall correctly. I'm not quite sure what you mean by "large-scale enterprise", but I'd hope Dell at its heyday would qualify.

Many parts of Apple's enterprise still runs on WebObjects, including the iTunes Store and the AppleID site: https://www.google.com/search?q=site%3Aapple.com+inurl%3Aweb...