Can Editor be network-enabled?

Would it be possible to network-enable the Editor? This would allow for collaborative editing.

I would think it would require some events be accessible in the Editor, analogous to Startup and Update (any others?) used to network things at run-time. Are there any such events? And could a network connection be thus established?

Look into 'ExectuteInEditMode' why not.

http://unity3d.com/support/documentation/ScriptReference/ExecuteInEditMode.html