I don't even think Graal would need to invest much to get something up and running.
Check out this open source project:
http://www.mapeditor.org/ (
https://github.com/bjorn/tiled)
Not sure how easy it would be to adapt to the level file format graal uses, but the editor is super nice.
Is there any ressources that explains graal's level data encoding? If not there should be, since everything seems to be community driven now anyways