Just so everybody knows, when the documentation over at cisco.com says you can’t mix modules for VPC links they only say that you can’t mix F and M series.  What they don’t tell you is that you can’t mix M modules either.  We recently had an M1 series module fail and tried to move one of the port-channel links to an M2 module, the command fails when you try to add the interface to the channel-group.

Why isn’t that in the same document that says you can’t mix F and M series?  I have no idea.  TAC told me that you can mix M modules for regular port-channels, but the VPC peer-link requires that they be the same model.