There is one more topology which reduces HV electronics to absolute minimum. Main disadvantage is needing a floating HV supply for each channel, not a big deal if there is only one channel. Another drawback is that the supply's earth capacitance appears as a load on the output stage, but that should be tolerable at 1kHz.
Note that an alternative way of dealing with limited SOA is paralleling output devices. For instance, Leonid Ridico's amp seems to be OK with about 40mA limit, so three such MOSFET pairs would get you to 100mA.