Has an AFL game ever ended 78-26?
Exactly once. On August 6, 1910, Sydney beat Geelong 78-26, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 78-26 in league history.
That makes 78-26 the 3884th most common final score out of 6,649 that have ever occurred in AFL. One point away, 79-26 has happened never and 78-27 has happened 1 times.