I use Kate for coding and note-taking. Sometimes it crashes - often when I've got a lot open. Unsaved 'real' documents (eg, ones backed by files, that have been saved at some point) usually have a backup/autosave type recovery file, that more-or-less works. Unfortunately, I've gotten in the habit of using untitled buffers (eg, pressing Ctrln in Kate) to store temporary notes.
Kate just crashed and I lost half a dozen of these. Does Kate store backups for 'new' files anywhere? I checked,
~/.kde/share/apps/kate/ and didn't see anything obvious ...
kate-editor 3.8.5 KDE 4.8.5 Ubuntu 12.04 (Don't remember if Kubuntu or Ubuntu + KDE, in case that makes a difference)