Service based ecommerce engine

My business is a translation agency and we're currently outgrowing our current system for managing customers, orders, suppliers and prospective customers.

I was wondering if there is any sort of open source content management system whereby we can;

- manage customer orders (individual order details, invoicing, account balance, newsletters, ticket system etc)
- link in our suppliers who are 99% of the time translators (link the supplier order with the customer order, suppliers will have their own invoicing and account balance etc)
- Be flexible so that we can customise various other features and develop our systems. e.g. I'd like to introduce an automated invoicing system for our suppliers to upload which will keep everything organised.

Some sort of CRM built in to all this would be pretty useful as well. (Currently using vTiger)


Thanks in advance