I found the most awesome chocolate cake recipe one day, and I no longer use any other. None hold anything close to it. People who normally don't like chocolate cake have exclaimed that it was great(!)...can they have more? lol I consider it to be way better than McCain's. It is not just that it is chocolate, but it is super moist, feels good in your mouth and has fantastic flavor. It has all real ingredients, nothing fake, which is the key to a great cake. Maybe it would be similar?
Unfortunately I was never able to taste ST's one of a kind cake. PM me and let me know what it was like. I will have some questions for you too. I might be able to use this recipe to fill the void you have.
Hopefully I can help.