I "think" the part that's hollowed out is just called "shift housing". I would be real tempted to see if I could weld up the hole & re-drill it. You probably can find one pretty easy since so many people switch over to manual transmissions. I think it can also be called a "collar" or maybe a "shift collar". It's the part with the PRNDL on it, right?
Now that I think more about it, I'm not sure if you can weld on "pot metal". What year/column are you working on? I've got one a '70 B-body laying around somewhere.