Currently NopCommerce version is not relay scalable.
Our client http://www.delta.co.il requested us to make site work with 30,000 concurrent connections.
With 5000 concurrent connection SQL is dying on AZURE with larger SQL scale.
Because Nopcommerce making around 50 sql requests for each page...
What we done:
To help client we built mirror on subdomain for home, category, product pages with readonly DB based on AZURE DATA TABLES, changed cart functionality to work with AZURE QUEUE and many more....
After it we successfully test the site front with 30,000 concurrent connections.
The adjustments you make for azure is nice but not going to make the site work with many concurrent connections. You should consider to change architecture.