I think Cisco has no modular 10GBase-T Transceivers, that are supported in any Nexus 5k or UCS FI. The only solution is Cisco Nexus 5596T Switch
The Cisco Nexus 5596T Switch (Figure 4) is a 2RU form factor, with 32 fixed ports of 10G BASE-T and 16 fixed ports of SFP+. The switch also supports up to three expansion slots. The switch supports 10 Gigabit Ethernet (fiber and copper), Fibre Channel, and FCoE, offering up to 1920 Gbps of throughput and up to 96 ports. The switch supports unified ports on all SFP+ ports. The 10G BASE-T ports support FCoE up to 30m distance with Category 6a and Category 7 cables.