In C#, there\'s the \"standard\" initializer technique { Property1 = \"a\", Property2 = \"b\" }, and there are a couple of special variants for collections (list and dictionary)
Using a variadic local lambda n that simply calls your constructor, you could get it as short as:
n
n(item1, n(item2, item3, item4), n(item5, item6))
Update: something like
var n = (params Node[] nodes) => new Node(nodes);