Can I make a networkbehaviour singleton class?

I have been using the following base class for singleton components:
using UnityEngine;
using System.Collections;

public class Singleton<T> : MonoBehaviour where T : MonoBehaviour
{
	protected static T instance;

	/**
      Returns the instance of this singleton.
   */
	public static T Instance
	{
		get
		{
			if(instance == null)
			{
				instance = (T) FindObjectOfType(typeof(T));

				if (instance == null)
				{
					Debug.Log(typeof(T) + 
						" instance is missing.");
				}
			}

			return instance;
		}
	}
}

Today I tried making a virtually identical class that inherited from NetworkBehavior because I had some networked game manager scripts that I wanted easy access to. So I just switched out MonoBehavior for NetworkBehavior. Things built fine in mlnodevelop, but the editor console immediately gave me. “UNetWeaver error: NetworkBehaviour NetworkSingleton`1 cannot have generic parameters,” and reported failure generating network code.

I’m curious what is causing this, and would like to know if there is an easy way implement singleton a singleton base class for network behaviors.

Bump.
I need to know this too.
I have a Game Manager singleton that extends Network Behaviour, but its variables are null when clients try to access it.