When did Yes play with two drummers.  I saw them with Bruford and then with White in early 70's.  Their recent tour was just with White.  Are you including Anderson's (or others) percussion?

Eardrum, ooops your'e correct, it was the album Yessongs that had both Bill and Alan listed, but were both at different gigs. as Bill had left and Alan just joined.

I may be wrong about Dave Clark too but i remember seeing a clip way back of a British band from the 60's (memory a bit hazy, may have well been another band, was the DC5 that rang a bell) but there was two drumers. Apparently Dave Clark was the vocalist and played drums but they got a better drummer in for sessions.