I had a little trouble tracking down the answer to what I thought was a simple question so I thought I would post it for anyone “googling”
The question was “Does FCoE work with fabric path?” Specifically my question was on the Nexus 5548UP in a single hop mode not FCoE multi-hop.
Some very smart people at Cisco dug up the answer for me and here it is as of 8/14/2014.
A device attached to a N5K leaf switch would be supported today with FP enabled, however the FCoE VLAN/VSAN traffic would NOT traverse the FP fabric.
An FCoE device attached to a N7K spine and/or next hop switch (MDS/Nexus) would be supported today, however only with dedicated FCoE uplinks to a Storage VDC and/or downlinks to an MDS/Nexus switch…essentially a parallel VLAN/VSAN network. This once again would NOT traverse the FP fabric.
An FCoE device in the future, with Dynamic FCoE, would allow FCoE VLAN/VSAN traffic
So translating slightly you can enable fabric path and run it on the Nexus, but your FCoE VLAN must remain classical Ethernet not fabric path. Apparently forwarding of FCoE frames over FP links is disallowed in the code.