My Victorian adventure The Journey Within keeps on getting longer - 6,500 words now, with no end in sight. I'm thinking it'll be about 10,000 words eventually. It's already the longest single story I've written.
I had a bit of a rethink yesterday though; parts of the plot weren't developing well and seemed to be heading for a dead end. I've started going back through with some fairly heavy editing to change one of the major plot components before I continue. I've had the idea for this one for a long time, just obviously never thought it through very well!