In NX-OS Mode, any of the -EX/-FX leaves can use the 40/100G ports as downlinks.
In ACI mode, that feature was introduced in 3.1(1i). I'm currently running thisversion in my lab with -EX switches with hopes to use these ports as routed uplinks, however I have not had a chance to implement/test the feature.
ACI 3.1 New and Changed information: Cisco Application Policy Infrastructure Controller, Release 3.1(1), Release Notes - Cisco