Here's the Lusca HEAD install under FreeBSD-7.2 + TPROXY patch. This is a basic configuration with minimal customisation. There's ~ 600gig of data in the cache and there's around 5TB of total disk storage.
You can see when I turned on half of the users, then all of the users. I think there's now around 10,000 active users sitting behind this single Lusca server.