As subject says... What is the biggest known system/site/community based on Orchard?

Would be intresting to see it.

Please post a link to the biggest community you know! :)

http://www.tacx.com

~70k users, ~1500 pages (incl. localized versions) 'at the moment'.

This is our work & the biggest site that I know ;)

Can you share any info about hardware setup required for this volume?

We're currently on a Xeon E5645 Hexacore with 12GB of RAM.

We're also getting a SSD soon to improve the sql server performance.