I have a nifty trick for this. You will need to use block syntax for the modules inside of the loop (find it here in the docs).
{% widget_block rich_text "my_rich_text_module" overrideable=True, unique_in_loop=True %}
{% widget_attribute "label" %}
My rich-text module {{ loop.index }}
{% end_widget_block %}
{% widget_attribute "html" %}
<h2>New Module</h2>
<p>Add content here.</p>
{% end_widget_attribute %}
{% end_widget_block %}
Notice 2 things:
1. unique_in_loop=true - makes the system name for the module unique
2. widget_attribute label - I broke the label loose using block syntax and set the loop index at the end to make it unique.
You should know that the ordering of modules using this method is utter chaos on the editor page. Instead of it display:
text 1
image 1
text 2
image 2
text 3
image 3
it will be more like:
image 3
text 1
text 2
image 1
text 3
image 2
It’s a bit of a mess. Makes for some pretty decent customization though.