Using REST API for data storage for user definable content

Question

I might be barking up the wrong tree completely however I am trying to achieve the following.

• Drupal 7.
• Custom REST web service which can hold user definable content types.
  • These pieces of content are stored and revisioned at a entity level. (not at a field level like drupal)
• I want to be able to use Entity API + Entity Model to define Content Types to store in the REST service.
• When inserting DO NOT create the Drupal field tables.

When I hook_entity_insert the field tables are still being created. How can I prevent Drupal from creating these tables.

Also, does this sound like the best way to go about this? Is there an easier way to achieve using REST services and not duplicating data in the Drupal DB?

Thanks.