container_view.coffee

Viz.WidgetsController = Ember.ArrayController.extend
  init: ->
    @refresh()
    setInterval (=> @refresh), 5000

  refresh: ->
    $.ajax
      url: @get('src'),
      type: "GET",
      context: this,
      success: this.loadData

  loadData: (visualizer) ->
    @set 'template', Ember.Handlebars.compile(visualizer.template)
    @set 'content', visualizer.widgets

Viz.Widgets = Ember.CollectionView.extend
  init: ->
    @_super()
    @set 'content', Viz.WidgetsController.create(src: @get('src'))

  createChildView: (viewClass, attributes) ->
    attributes.template = @getPath('content.template')
    attributes.templateContext = attributes.content
    @_super(viewClass, attributes)

# <h1>Surrounding HTML</h1>
# <div>{{view Viz.Widgets src="/visualizers/hosts"}}</div>

This example was for a very specific case where dynamically loaded templates based on a view attribute were required. You could probably have a separate state manager for the data loading per view, but it seems like overkill here. I'm not sure if dynamic controllers generated by views is a perfect pattern, but on occasion I use it and it works nicely.