Somewhere recently I read about a trick to shorten long cardigans by wearing them upside down. This may have been in Link Love, but I can't find it. If you know of it, please add the link.
I decided to try the idea and took some quick photos of the results. I can see this working well with a dress or skirt.
It seemed easiest to manage by spreading the cardi on the bed, opening side up and top to the edge of the bed. With my back to the bed, I slipped arms into the sleeves and adjusted the bottom of the cardi around my neck like a shawl collar. What do you think? I have not actually worn any of these out. The cardigans used need to be fairly long. Shorter ones form a bolero type topper.