How to pass along current $form_state for an #upload_validators callback?
It appears we can use this code to get the $form_state, however, there are no $form_state['values']. 

$form_state = form_state_defaults();
// $form_state is passed by reference and will be updated automatically.
form_get_cache($_REQUEST['form_build_id'], $form_state);

I was able to find the value in 
$form_state['field']['field_NAME']['und']['entity'][0]-&gt;field_NAME['und'][0];

However, this will not pass along the value you set in another field without first setting an #ajax callback on that field, the callback can just return NULL, it is just to update the form.

In our case we disable the file upload field until the other field has first been set. 

Hopefully this will help someone or most likely myself in a year from now.

sources: https://twitter.com/eojthebrave/status/743544054030336000 &amp;&amp; How do I load the $form_state for a form loaded with drupal_get_form?