Include entries to a entries section object, without 'merge'
A colleague of mine shed some light on a very simple solution

{% set myPages = craft.entries.section(['structureName', 'singleName']).order('sectionId desc') %}

&lt;nav&gt;
{% nav entry in myPages.level([1, null]) %}
  {{ entry.title }}
{% endnav %}
&lt;nav&gt;

&lt;aside&gt;
{% for entry in myPages.level(2) %}
  {{ entry.title }}
{% endfor %}
&lt;aside&gt;


Passing an array of handles/slugs instead of just a string works perfectly. Since singles don't have levels; defining null in the level pulls them out too.