A class for handling starting and stopping of coroutines. Haven't tried it out yet, seemed like a neat idea

CoroutineRunner.cs

using System;
using System.Collections;
using UnityEngine;

public interface ICoroutineRunner : IDisposable
{
    	/// <summary> 
    	///     The MonoBehaviour running the coroutine
    	/// </summary>
    	MonoBehaviour Runner { get; }
	
    	/// <summary> 
    	///     Set the coroutine runner
    	/// </summary>	
    	void SetRunner(MonoBehaviour runner);

    	/// <summary> 
    	///     Start a coroutine on the runner. This will stop any already running coroutines
    	/// <exception cref="NullReferenceException">A runner must be set before the coroutine can be run</exception>
    	/// </summary>
	void Start(IEnumerator coroutine);
    
    	/// <summary> 
    	///     Start a coroutine on the runner. This will stop any already running coroutines and set the runner
    	/// </summary>
	void Start(IEnumerator coroutine, MonoBehaviour runner);

    	/// <summary> 
    	///     Stop the currently running coroutine
    	/// </summary>	
	void Stop();

    	/// <summary> 
    	///     Implementation for IDisposable. Stops the coroutine and sets the runner to null
    	/// </summary>	
    	void Dispose();
}

public class CoroutineRunner : ICoroutineRunner
{
	public MonoBehaviour Runner { get; private set; }

	private Coroutine coroutine;

	/// <summary> 
	///     Create a new coroutine runner. You will need to set a runner on Start or call SetRunner
	/// </summary>
	public CoroutineRunner()
	{
	}
	
    	/// <summary> 
    	///     Create a coroutine runner with the runner already set
    	/// </summary>
	public CoroutineRunner(MonoBehaviour runner) : this()
	{
		Runner = runner;
	}

	public void Start(IEnumerator coroutine)
	{
		if (Runner == null)
			throw new NullReferenceException("Runner", "Cannot start coroutine, no runner set");

		Start(Runner, coroutine);
	}

	public void Start(IEnumerator coroutine, MonoBehaviour runner)
	{
		Stop();
		
		Runner = runner;
		this.coroutine = Runner.StartCoroutine(coroutine);
	}

    	public void Stop()
	{
		if (Runner != null && coroutine != null)
		{
			Runner.StopCoroutine(coroutine);
			coroutine = null;
		}
	}

    	public void SetRunner(MonoBehaviour runner)
    	{
    	    	Runner = runner;
    	}

	public void Dispose()
	{
		Stop();
		Runner = null;
	}
}