Monitoring 10gig.

We are currently in the process of deploying Bro on a 10gig network, and
I am inquiring as to who of you out there have this setup or any incite
as to what hardware should be utilized? My first thought was to use an
appliance like a Gigamon to spread out the traffic to multiple workers.
This being a costly item are there other avenues to use such as SPAN
ports and the like?