How to mix databound and static levels in a TreeView?

Question

I have a collection of Database objects, each containing collections of Schema objects and User objects. I want to bind them to a TreeView, but adding

Answer 1

Here's a modification of Josh's solution to work with SMO (my original problem statement):

and the modified converter:

public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
    FolderNode[] result = new FolderNode[values.Length];
    for (int i = 0; i < values.Length; ++i)
    {
        result[i].Items = (IEnumerable)values[i];
        result[i].Name = values[i] is UserCollection ? "Users" : "Schemas";
    }
    return result;
}

Attribution Note: Content copied from OP's final solution, posted as an edit to the question, rather than as an answer