Actually the 'bridge' issues is similar for transistor amps. With *any* bridged amp, both speaker terminals should be kept from ground.
BTW, ESLs in general are best driven by tubes. If you plan to do it with transistors, you will need a much larger amp due to the impedances and impedance curve of the speaker- Sound Labs are an excellent example of this: a 200 watt tube amp will play every bit as loud as a 400 watt transistor amp because the transistor amp will only make 200 watts into the load. In some cases, the 400 watts may only be 50! That's why tubes are the traditional choice for ESLs.