I found this online recently. Kudos to the author, as this is very handy for those that aren't totally comfortable with the XmlEdit (XmlDialog) feature in Xmlspawner. It seems the "Connect" option is broken, that would be because it hasn't been updated since 2008, but you can still load and export NPC files. There are some shortcuts for adding common things, like Attachments, SimpleMap, SimpleNote, TempQuestObjects, etc. I'm not going to offer any support for this, as I didn't create it, but the source is available if someone wants to pick it up and update it I guess.
https://xmldialogeditor.codeplex.com/
https://xmldialogeditor.codeplex.com/