Well, Butterfly had two as work tools to fit different sized kids.
One is a Dawes 2Across, the other is an Orbit, er, SomethingorotherprobablyaLibraIIRC.
I have custody of Pagan's KHS, which was our first, bought from JD with a view to getting the wean mobile (and indeed helping him transform into Superstoker). I bought a 531 (what else?!
) Orbit touring tandem when Pagan & I divorced, but timing chain issues meant that I borrowed the KHS anyway. Both are now in store in Yorkshire.
Since then, Butterfly & I have discovered we both really like tandemming, and she says that it's a good way to make sure I don't zoom off without her*, so we bought a Dawes Super Galaxy. :thumbsup
* Disclaimer: I have never knowingly zoomed anywhere