http://www.cisco.com/en/US/docs/ios/lanswitch/command/reference/lsw_s2.html#wp1108357

Hello Observium Community,

Before I add a feature request to JIRA and/or start work on
      an idea I have: I'd like to discuss it here briefly.

I have a cisco router terminating a QinQ trunk on a
      GigabitEth port, the 2 tags are actually 802.1AD "translated" to
      cisco `ISL', and I would like to track the bit/s t/p on each
      (outer) S-TAG.  There's no interface that corresponds to the S-TAG
      only; you get the entire trunk or several thousand sub-interfaces
      which correspond to the C-tags.

The router has no trouble at all keeping a counter on the
      S-TAG level vlan
s:

ROUTER#show vlans dot1q

Total statistics for 802.1Q VLAN 1179:

   1043211296 packets, 392860154434 bytes input

   1318271657 packets, 1413383465338 bytes output

Total statistics for 802.1Q VLAN 1180:

   12901924856 packets, 5689677372911 bytes input

   16833259171 packets, 17373955952108 bytes output

So, the 1st task would be to find the MIB, if any for these
      "outer" tags, and attempt to write code for an add-on to discover
      and graph them.

      Any one "been there, done that" as yet?

-- 
http://about.me/terry.sweetser