genesis for enterprise sites

[fogger]

Hi
After I was directed to here http://designsbynickthegeek.com/tag/genesis-explained
I found answers to almost every question I ever had about genesis, How to expand it and more.. Thank you Mr Geek..:)
Recently I was asked if Genesis could scale to handle 50,000 users on a basically enterprise size web site.. I saw that with new hosting Studiopress offers and I said it might be possible.
However another developer in our office said it had to be rails..He told the manager
that Rails is used on some of the bigger sites..(he sited kickstarter and others)
I am part of a small web shop and I am the Wordpress guy I like Genesis..
Anyway..Im just looking for more information to prepare my proposal..
Any links or advice from any Genesis experts here would be much appreciated.
I know I can look at the showcase it has tons to examples..but no real larger financial sites.(that I saw)
Thanks
DAN