There were a couple of Joe Walsh tours where he had Andy Newmark and another I can't remember and another tour where he had both Joe Vitale (big surprise) along with Russ Kunkel.
Newmark was with Vitale, documented on "You Can't Argue With a Sick Mind."
Kunkel and Vitale were on the 1981 "There Goes the Neighborhood" Tour. They were throwing sticks at each other and catching them during the breakdown of "Funk #49."
In another post, I described a November 2011 jam session in which I set up two kits. With the right person, it can be very powerful and a lot of fun. We were able to lock in for some unison parts that drove the crowd nuts, and at other times split up parts that would have been difficult for most to play alone but were simple when shared. It was amazing what we could accomplish just jamming, a little rehearsal would have been most impressive.
There is something alluring about it, even if it's not always appropriate. There were a few times where I wanted to step down to let one drummer play alone, but the guitarist who was the guest of honor wouldn't allow it.
It does require two sympathetic players with big ears to pull off.