Vernon used to race 3/4 mile races back in the 70s and 80s. Just made it closer to half mile racing because you didn't have the long run before the 1st turn like they did when going a mile there.
One of the Canadian tracks (maybe Georgian Downs) used to have a special day where they raced all kinds of different distances, I think they went as short as 1/8 mile and las long as 3 miles. I think the 3 mile race had 16 horses.