duck

public class Sequence {

    private static GameObject[] _items;
    public static GameObject[] items {
        get {
            if (_items == null)
            {
                _items = FindObjectsWithTag("Sequence Item");
                _items.Sort(new SequenceObjectComparer());
            }
            return _items;
        }
    }
}

public class SequenceObjectComparer : IComparer<GameObject>
{
    public int Compare (GameObject a, GameObject b)
    {
        int a_id = ParseNumberAtEnd(a.name);
        int b_id = ParseNumberAtEnd(b.name);

        if (a_id > b_id) {
            return 1;
        } else {
            return -1;
        }
    }

    public static int ParseNumberAtEnd(string text)
    {
        for (int i = text.Length-1; i >= 0; i--)
        {
            if (!Character.IsDigit(text[i]))
            {
                if (i == text.Length - 1)
                {
                    Debug.LogError("No digits at end of GameObject's name: "+text);
                }
                string digits = text.Substring(i+1);
                return int.Parse(digits);
            }
        }
        // Text is entirely made of digits!
        return int.Parse(text);
    }

}