Both Cisco and Brocade can do this
The Cisco Nexus 5000 and the Brocade 8000 can be used exactly like the Xsigo and VirtenSys solutions, using FCoE as the storage protocol, and Ethernet as the fabric.
Half-height and blade mezzanine FCoE Converged Network Adapters (CNAs) are available today from QLogic, and will soon be available from Emulex and Brocade. Blade mezzanine CNAs are available today from QLogic, and will soon be available from Emulex.
Storage administration (zones, LUN masking, etc.) in an FCoE environment is identical to a pure Fibre Channel environment. Ethernet management (VLANs, etc.) in an FCoE environment is identical to a pure Ethernet environment. Management concepts unique to Fibre Channel and to Ethernet are mature and robust. Only FCoE specific features (FIP, etc.) are new. This means a minimal learning curve for FCoE compared to InfiniBand or PCIe based networking.
There is little reason to use Xsigo unless you have a need for an InfiniBand network beyond I/O consolidation. Xsigo might be the best solution for an InfiniBand HPC cluster. As there is little existing PCIe based networking in the world (except in the cPCI based real-time and networking space), the only place VirtenSys' technology makes sense is in those markets, where the customers already know PCIe semantics.