I saw Ben-Hur at the Loews State and though the screen was the widest I had ever seen I can not be 100% certain whether Ben-Hur was shown at 2.55:1 or 2.76:1. Though I tend to believe that it was 2.76:1.
I've always had a chuckle viewing the Parade of the Charioteers as well as the race itself due to the shifting sun and shadows. It's great anyway flaws and all.
While there is no CGI there are plenty of cinematic 'tricks' at hand. Matte paintings are used throughout including quick glances at the total crowd scenes in the chariot race. That said a most impressive movie for its time and perhaps out time. Can't wait to see the blu-ray.