If I am not wrong then

Dual uplinks are supported in the following modes of operation:

1) If there are two sups in the device, you can have the first TenGig of
each sup active and acting as an uplink.

or 

2) If there is a single sup in the chassis, then two interfaces on the same
sup would be active and acting as an uplink.

You cannot have dual uplinks on a single sup active when dual sups are
installed in the system.

Check This out

http://www.cisco.com/en/US/docs/switches/lan/catalyst4500/12.2/52sg/configuration/guide/RPR.html#wp1097897

When you select 10-Gigabit Ethernet uplinks on WS-X4516-10GE and WS-X4013+10GE Supervisor Engines in RPR or SSO mode, only TenGigabitEthernet 1/1 and 2/1 interfaces are available. Similarly, when you select Gigabit Ethernet uplinks, only GigabitEthernet 1/3, 1/4, 2/3, and 2/4 interfaces are available. When you select to use both uplinks concurrently, TenGigabitEthernet 1/1 and 2/1 interfaces and GigabitEthernet 1/3, 1/4, 2/3, and 2/4 interfaces are available.

Hope this helps.