Since the views allow you to define functions, you I would expect you can use a recursive call to display the child items (warning the following code has never seen a python interpreter):
define a function: {{def showtree(tree):}} <ul> {{for i in tree.items:}} <li> Displaying child {{=i}} {{showtree(i)}} </div> {{pass}} </ul> {{return}} usage: {{showtree(mytree)}}