Are you looking to build something or a preconfigured "enterprise" solution?
For a custom solution:
BLUF: A 1000base router is easy. Utilizing SFP may be a bit trickier due to drivers. I found ESXi along with another flavors of virtualization can be a good work around.
The long answer with experiences:
I'm doing 10gb utilizing ESXI's VMXNET2 virtual NIC on a pfsense guest. It took some time to get the VMXNET2 driver to work under pfsense, but it seem to work ok. You will have to update the stock pfsense install with the latest bsd NIC drivers. For 1000 base, just use the standard E1000 virtual NIC. For external ports, I'm using an Intel X540 network adapter. I have not had a chance to test 10Gbe through the pfsense vm yet.
I have minimal experience with SFP, so take my next sentence with a grain of salt. You should be able to use an SFP PCIE card which would present itself as a NIC capable of being attached to the virtual network. Pfsense and most BSD based firewalls don't play too well with a lot of newer cards due to lack of drivers. Most open source routers, especially BSD based tend to be behind the times of driver support. This is one of many reasons I virtualized my router. It aids me in getting around the driver issues.
My solution is working well for me. I do notice my processor can get hit hard at times with large and fast transfers between guests (one of which is Openindiana for ZFS raid) and physical hosts which peaks my ESXI box out around 60% utilization across 8 x L5520 cores. I'm successfully transferring at 400MB/s sustained between 2 nodes which is maxing out my SATA controller. If I had SATA III or SAS II for my SSDs, I'm sure I could do better. For the moment, the setup is in my C6100 for testing purposes and I'm limited by it's hardware.
One thing that would be important to you is how well pfsense can handle the workload. This will be highly based on how many features you are utilizing on your router. For instance, if you are using intrusion detection, proxy, content filters, etc, expect a performance hit if your processor isn’t strong enough. Newer hardware shouldn’t have much issue. My 10Gbe transfers are just going through the Vswitch, not through the pfsense VM. Testing pfsense max throughput is a project in my future.
Since your only looking for 1Gb, I don't think you would have an issue. 1Gb is not that resource intensive and there are a lot of individuals and corporations using pfsense in that manner. I have the 1gb onboard NIC dedicated to the cable modem. My connection is faster than what a 100base card can handle but nowhere near that of a 1000 base. My internet is definitely not hampered by the network cards/pfsense box. A couple years ago, I had a dedicated pfsense box set up with 1gb cards, one for private LAN, and one for public LAN. I had no issues transferring at 1000base speeds through the router. The part of equation I cannot attest to is SFP.
For 10Gbe purposes, I have not had a chance to optimize my setup. If you look for the 10gbe network thread, it provides some tips to increase your router/VM's efficiency. Some things it mentions are customizing your IRQs and dedicating processors for network traffic.
All I can say is, do your research and maybe get some others to chime in here.