How import Feeds into entityforms
Other than Migrate (which I have not tried yet), the only thing I have found was to use Feeds Import with the contributed patch for a Generic Entity Processor to import Entityforms.

https://drupal.org/node/1033202#comment-7710367

I currently have Drupal 7.23 and Feeds 7.x-2.x-dev (7/6/13) and I patched the feeds module successfully with the patch at comment #217.  This then gives you the option of having an entityform as a bundle.

I created a test entityform, a small test csv, and a new test feeds import.  The import completes successfully, but there's no content in the submissions.  Maybe you'll have better luck than I.  My next step is to checkout the latest from git and try again.  If that doesn't work, I guess I'm going to have to learn how to write a migrate module.

FYI, I have successfully used the Feeds Import module using the node processor that comes with the module for custom content types if you don't need it as an entityform.  There are several good Feeds videos out there is you're not familiar with the module.

Please reply if you find something else that works.