I'm boxing on Khaz/Dath Horde side, just me and my partner active in our the the guild these days though.
(Partner boxes as well, although they're not interested in pushing Mythics. They have altitis and its more efficient to spread them across accounts and box)

Currently playing around mainly with a pal/druid/lock/hunter/hunter combination for Mythics when I get the time for the fun of wiping over and over
I seem to be all thumbs when it comes to not standing in crap and moving the ones I'm not driving.

Although its quite common for one or the other of us to be out and about with 2-5 characters for dailies, world bosses etc..

We've both come across least 1 other boxing. A team of 5 hunters and I ran past 5 a pally team when i was leveling a 2 pally/3 hunter team in Draenor not that long ago.