Mega-Mario has released version 2.0 Beta 2 of his editor for Super Mario 64 DS.
This editor is compatible with both US, the EU, and JP ROMs, and currently has level editing as it's main feature. With the ability to edit warps, camera placement, objects, and even multiplayer levels this editor is certainly not slim on features. Model editing is included, but experimental, and more features are planned for the future.