Charge Pump - pre-existing ICs?
The Analog Devices (via Linear Tech) LTC3751 should work for you.

From the product page:


  The LT3751 is a high input voltage capable flyback controller designed to rapidly charge a large capacitor to a user-adjustable high target voltage set by the transformer turns ratio and three external resistors. Optionally, a feedback pin can be used to provide a low noise high voltage regulated output.


If you don't need the voltage regulation, you can use the LT3750.