I know that this question was asked before. But I see the responses are quite dated (at least in comparison to the pace we move).
So I am asking same question again.
We are about to start a ground up project to build a multi-tenant platform which will support basic e-commerce (will extend later) and basic CMS for feeding the catalogues. As this is targeted to a huge focus market and expected hit on certain event would go up to 20K (concurrent), we are moving away from platform like magento and thinking about building our own.
As per today's date the only "silver bullet" is node.js (pun intended) - so we plan to use node in backend, html5/KO in front end and still debating between mongoDB and MySQL.
In that context, would love to know is there any node.js/html5 based open source eCommerce platform (along with semi sophisticated cms) available today. Even beta or alpha will do so that it gives us a start.