While browsing the tcpdump-workers mailing list I came across a post describing the The Meta Traffic Processor PCI Card. This device "is a standard 32-bit/33MHz, PCI half-card with two copper Ethernet ports. The MTP appears to the host's operating system as a standard network interface card capable of enforcing from 600 to 1500 stateful policies to capture and/or block specific packets. The policies can be directly derived from public domain signatures or they can be completely user defined." These "policies" can be Snort rules or one day BPF filters.
The product appears to be the result of work done for a NSF grant. Metanetworks founder Livio Ricciulli described his project to NANOG in May 04.
I had heard from a .mil type that DoD was working with a vendor to run Snort-like applications in hardware. Perhaps this is what he meant?
I intend to contact Livio to see if his card works with FreeBSD.