After some brawling with LINQ, Restructuring the code, a guy who went homicidal on our car and exams, the latest version has been added. Now all ship entities are featured in the editor, only brushes and original entities in the mods manifest are shown and the main list box in the overview and the collection of entities are automatically updated when needed.
The brush previewer was not included as I wasn't sure how much more work it would take and I decided to concentrate on supporting more entity types first.
Feel free to comment, especially if there is anything you would see changed or if you have any ideas for new future features.