If they included a 4th disc with a further 20 shorts, then this would be 80 shorts for 80 years.
If I had my way, these last 20 shorts would be:
1. Porky's Hare Hunt
2. Presto Change-o
3. Hare-um Scare-um
4. Elmer's Pet Rabbit
5. Hiawatha's Rabbit Hunt
6. All This and Rabbit Stew
7. Crazy...