I wanted to announce that our free product data export software for AspDotNetStorefront now supports multiple store export.
You can download it from here:
https://www.atensoftware.com/p181.php
It is not set up as a add-on, but you just copy the two files to the root of your website. When you open the URL to the page, you will see choices to select the specific store whose data you want to export.
This exporter is designed to be extremely high-performance and light-weight, and quickly exports data in CSV format from stores with thousands of items. (It was designed to work with a store with over 100k items.)
This export script is designed to work with our CSE product data feed service, which can feed your products to Google Shopping, Amazon Product Ads, NexTag, PriceGrabber, ShareASale, TheFind, Bing Shopping, Shopzilla, Shopping.com, and many others.
Regards,
Shailesh