3V input , 1000V/100uA output power supply

Now i am design a power supply.

the input voltage is 3V, output voltage is 1000V/100uA.

input voltage source is two batteries.  

first i use tps61040dbv boost the input voltage to 75V, nest step is boost the 75V to 1000V.

I want use capacitor pump to boost the voltage, but  using some IC plan may be better.

i hope some advice.

thanks every one.