Hi forum,
this is more aimed at a staff member response, but perhaps if someone attended a MUM where it was discussed you may also know the answer.
Basically back in Newsletter 82, the new switches with QSFP ports mentioned this in the description:
“40Gbit stacking support”
Is this just to say give a good switch ↔ switch connection but still rely on STP for looping/redundancy, or is this to say the QSFP ports will be able to be used and the software will support proper ‘stacking’ i.e. single management, shared ARP tables, and perhaps dare I say multi-device LACP (for some real good redundancy)?
If my dreams come true, I hope its not a coveted ROSv7 feature 
and we see it in v6 