OmniOS + Nappt-It can serve FC targets with no issues.
You will want to use the QLE-246x series adapters for both ESXi and OmniOS, it is easily put in target mode in OmniOS and has native ESXi support.
From there you will either be doing point-to-point FC, or you will need a FC switch. For home use a Brocade 200e is a good choice. Try to find one that is fully licensed and comes with some SFP's.
Configuration is pretty simple once OmniOS + NappIt is installed, the adapter is put in target mode and you have a pool configured. You just create one FC Target and share it to the rest of the WWN's. Format it on 1 ESXi box then refresh the targets on the others.
All that being said:
1. Do you really NEED more that 1Gb thruput on your storage?
2. Are you going to have more than 2 hosts? If not, point-to-point 10Gb will be cheaper and faster.
3. Do you really need more than 1 ESXi host? AIO is a little bit more expensive up front, but lower power usage in the end.