[Zope] Zope for medium/large sites

Hi! We're considering using zope for a somewhat large project: It's a VPN for arround 10.000 institutions ( >100.000 users expected, up to 1.500.000 users possible, but not likely). Hundreds of simultaneous connections expected. The database has to support >100.000 users and a LOT of content (more than 1000 virtual hosts, along with a very big main site). The question is: Is zope up to this? And yes, the necessary hardware is available 8-). We've used Zope for smallish internal projects, but for something as this... Best regards, Tiago