Hi
To clarify a bit, you would only need 100 CPU licenses if you wanted to run NSX on the entire environment. You can run it only on a subset like say one cluster that needs more security than others for instance. Plenty of customers start that way.
Also, since you're running vCloud Suite, there is an add-on SKU for NSX that is not the full price you'd pay for NSX on its own. Finally, for that many licenses, there's no way you'd pay list price - there's lots of things your VMware sales rep can do with pricing at that scale. If you don't know who your rep is, email me directly at showard@vmware.com and I'll get you connected.
Thanks!
Sean