techiejay2

Thanks everybody for your replies.  I had a look into the various options suggested here, and since it'll be hanging over people's heads and in quite a noisy environment, I opted for the Doughty modular system - a clamp, an adjustable drop pole and a single stirrup on the end, then couplers attached to the cameras.

For those asking, they're Datavideo PTC-150s, meaning their screw threads are all in US/Imperial sizes, so next headache is finding the right bolt, but thanks all for your help, I really appreciate it.

Sorry to bump an old(ish) post, but did you find anybody in the end Mark?  Would be interested to know how you finished up with this idea, as we find ourselves in a very similar position!