I am trying to determine if the Sup8L-E uplink ports have the same limitation as the Sup7L-E. In the Sup7L-E, in single sup configuration, you can use all 4 uplink ports but only when doing all 1G interfaces. If you are doing two 10G, you have to use the first two ports and ports 3 and 4 cannot be used. If you are doing 10G and 1G, you have to use the first 2 ports and ports 3 and 4 cannot be used. If you are doing all 1G, all 4 can be used.
I'm not sure if that same limitation exists with the Sup8L-E. I looked at the ASIC diagrams from a Cisco Live presentation and they are very different, but the 8L-E diagram does not necessarily show that you can mix and match on all 4.