To be able to mirror at block level you would need a HBA that could perform this and I dont know of any that can do this for iscsi or FC. However there may be a qlogic SAN/switch that will perform this for you but I am not sure.

As for a switch that will provide GB ethernet and FC fabric I dont think there is one and would not recommened a common switch.

We have used block level replication between to DSS servers and if one fails we perform a manual failover (until the new release of DSS that will have auto failover). We use the 2 x brocade 16 port FC switchs between our servers and the storage servers in a mesh configuration so that we have redundency on all aspects from FC Cards to FC switch. We then use a GB cisco switch from our workstations to the servers.

Brocade FC switches are expensive, however qlogic do have some entry level FC switchs/SAN