That's just one of the possibilities. You can either do the cheapo one-line-driven-by-inverter trick, or use a transformer or a differential line driver (like 8903A output stage); basically the opposite of an instrumentation amp. These behave pretty much the same as a transformer, i.e. they have high common mode output impedance. Available in chip form as well, e.g. DRV135.

Problem is the circuit needs very accurate resistors and needs to be carefully balanced, just like an instrumentation amp.