Finding/Implementing a digitally-controlled high-voltage switch

I am looking for a switch or relay to switch high voltages on and off based on a digital input signal. Below are the characteristics of the device.

Switching frequency: 100 Hz to 100 KHz
Input (control) signal: square waves, 3 to 12 volts amplitude, 100 Hz to 100 KHz range
Input voltage to be switched: 0 to 5 kilovolts DC, 1 milliamp (max)
Output signal: square waves, 0 to 5 kilovolts amplitude, same frequency as control signal
Load: capacitive load (several picofarads)
Cost: not more than $100 per switch

Thanks for any info you can contribute to this!