It's possible, yep...and it's been discussed, just never implemented. It was one of the first uses of SetName() with the 1.67 release, and we set it up for testing with the horses, since their numbers are fairly limited. Since there's been no apparent issues with this, I don't see any reason why not to add the feature. It's about a 10 minute thing, but when you're going through a long list of changes and fixes, "naming oxen" doesn't tend to pop up very prominently.
I'll try to get it put in for the next update, but heh...might slip past me again.