The pot itself helps to control the size; and you can definitely keep it to 6 or 7 feet. The best method is drop crotch pruning (google it, if you don't know). If you prune off the new growth, you won't get any fruit.

I will look that up John. My Bearss lime is over 6' in a pot and I can't allow it to get much taller. It is loaded with fruit though.

Always easier to prune when it has fruit; because there is less danger of cutting off your fruiting wood.