What's your climate/location/soil moisture situation? This affects how much the running bamboos will run. So, for example, Ph. aurea doesn't really run much at all in many UK gardens, especially in the parts of the country, but it is seriously invasive in many other countries with more summer warmth and more water availability, and I suspect in damper/milder parts of Britain too. But the kind of locations where runners don't run much, you'd be lucky to persuade anything to grow anything like 6m high.

Thamnocalamus is another cool climate clumper that grows higher than Fargesia, though 20ft would still be rather good going. They aren't as hardy as Fargesias though, only for places down to about -12C (10F), and are less hardy than that when young. They are happy in fairly shady locations, though if you can give it some wind protection while it is being established that would be a good idea too. Give it a lot of water and food, might get it up towards 6m.

There are some clumping Borindas that grow big, though they are even less hardy than the Thamnocalamus, and are expensive.

Semiarundinaria fastuosa is the classic tall hedging bamboo. It is a runner, but I've heard it claimed that even if you can't confine it completely, because it tends to run in long straight lines, provided you confine it locally here and there it you can point it in the right direction, and not have too much of a spreading issue. How true this is in reality, I cannot say.