Another option could be 'parable'. Parables are short stories that convey a religious or moral lesson. While they are generally short, some parables can be more elaborate and thus considered a 'long short story' in relation to the crossword clue. Parables are found in many religious and cultural traditions, like in the Bible for example, and their length and complexity can differ.
It could be 'novella'. A novella is longer than a short story but shorter than a novel, which might fit this crossword clue.
It could be 'yarn'. A yarn is often used to refer to a long, rambling, and perhaps even fictional story.
Perhaps 'epic'. An epic is a long narrative that often involves many characters, complex plots and sub - plots, and a wide range of events. It can be a story of heroic deeds, like 'The Iliad' or 'The Odyssey' which are classic examples of long, involved stories.
Novel. A novel is a long written story, which is a very common answer for a crossword clue like 'long story'.
Epics could also fit. Epics are long narrative poems or stories that often deal with heroic deeds and adventures, so they are a great match for the 'long stories' crossword clue. They usually have a complex plot and a large number of characters.
A 'tale' could be an answer. Tales can range in length from very short to relatively long. They are a form of short story, and if it's a more extended tale, it can be seen as a 'long short story' which would work for the crossword clue.
One answer could be 'yarn'. 'Yarn' can mean a story, and it can be used to describe a long short story in a more informal way. For example, someone might say 'He spun a long yarn about his adventures.', which implies a somewhat long story that still has the essence of a short story.
It might also mean the highest level or floor in a building in some cases. Say, in a crossword that has a lot of architecture - related words. If the clue is something like 'Top Story in a Skyscraper', then it's about the topmost floor.
Maybe it's something like 'film footage' or 'video capture'.
It could be a word like 'plot' or 'tale'. Those are common terms associated with narratives and stories in crosswords.