[BennyB]

Tim the Canadian team at the Worlds had a counterbalance system based on two floats about 6-8 feet apart and attached with a metal pole of some type. I only saw it once when they walked past on the beach but you could probably get in touch with them to get the specifics.

Something as simple as two floats with a broomstick separating them could potentially work though you might want a bit more distance between them to ensure the unconscious diver doesn't receive a rescue clonk on the head on the way back up.

Cheers,
Ben