With Gibraltar's Long Cymbal Boom Ratchet Assembly you can mount an extra cymbal to a pre-existing cymbal stand (or any other piece of hardware with a small rod).
One side of the ratcheting clamp is dedicated to holding the included boom arm, which in turn can hold any cymbal at the top. The other side of the clamp is able to grab firmly on to any other small rod, including boom arms on other cymbal stands.
With this piece of gear, it's completely possible to have a single cymbal stand with two different cymbals branching out of the top.
