simple stupid code :/

gistfile1.cs

        static IList<ViewModel> registeredEntities;

protected static IList<ViewModel> RegisteredViewModels
        {
            get
            {
                return registeredEntities;
            }
            set
            {
                registeredEntities = value;
            }
        }      

public ViewModel()
        {
            if (RegisteredViewModels == null)
                RegisteredViewModels = new List<ViewModel>();
            registeredEntities.Add(this);
         //...
        }