As far as UCS goes...
...the current chassis architecture wouldn't really allow for true FC down to the blade. Reverting back would also mean stepping blade technology back 5 years if not longer.
Once the FCoE traffic hits the Nexus Fabric Interconnects (excluding the Nexus 10k I believe) it can be broken out into FC anyway. So yes that does play into the "top of rack only" argument, but is that really such a bad thing compared to the old way of having 4 modules in the chassis (2 eth, 2 FC), 2 or more NICs/HBAs in each server, top of rack ethernet and FC switches and so on?
To more-or-less echo the EMC and HP bods who have already posted: regardless of whether it's Cisco UCS or HP FlexFabric, having FCoE down to the chassis/blade doesn't seem like a bad thing to me. From my viewpoint, converging LAN and SAN at the server level is a good, viable, cost effective thing to do. And you can hardly call it a dead technology when every blade vendor on the planet has taken the same approach. We're also seeing the technology move from blade servers to rack servers (UCS C-series for a long time, HP FlexFabric switches and CNAs more recently).
It might evolve from the dream of a complete "FCoE network" to a more confined remit of "converged server uplink technology" or some-such, and while that role might be less glamorous it's clearly alive in that capacity. More to the point is that in that use case it's really popular with customers as the bottom line is it reduces cost.
So to summarise this dying protocol...
1) It's used by multiple companies in flagship products (blades).
2) It's being developed by multiple companies to bring it down to more mainstream products (rack servers).
3) It's popular with customers.
4) It's cost effective.
5) It's evolving to find its place in the market.
Yup. Clearly this is one protocol that's as dead as a doornail.