Large scale site

I was just thinking through while building large scale application on top of Drupal on dealing with below aspects..

• Multisite with Multiple countries and languages. (1 site with 4 countries, each country with 4-5 languages)
• Data import capability for dumping data from external sources via CSV/xls/sql etc
• 3rd party mash-ups integration (say Amazon, iTunes, Soundcloud etc)
• SAP system integration
• End to end CRM application
• B2B features with -E-commerce support

If we are going to have single Drupal code base and porting all of them on one side, how much Drupal can sustain.