Sizing suggestions for Bro 2.2?

I have a network with about 3500 network devices spread across multiple subnets, some private and not routed off our internal network. I have mostly 1Gb right now, with some limited SAN networks at 10Gb. I'm guessing I'll want to be able to handle a network core of 10Gb though as we expect to be running that soon for certain links between buildings and out to experimental stations. Our campus backbone link will also be 10Gb soon.

I think currently I am most interested in network traffic from our internal untrusted subnets and VPN subnet to our public and trusted internal subnets.

What additional information should I provide, and what sort of hardware should I expect to run Bro on Scientific Linux 6.4?