Interested in creating high voltage regulator...

[DaveHardy]

I'm interested in creating a high voltage regulator that is capable of delivering about 250 to 300v with minimal ripple and almost no load.   Furthermore, it must have excellent short circuit protection.  I plan on using a Villard cascade voltage multiplier circuit to get me up to where I need to be from typical +/- 15v transformer secondaries.   The Villard cascade multiplier can deliver high voltages, but there is a huge amount of ripple on the output of it - close to 40v.    I've found a few circuits that appear to do the trick on paper, but I'm not sure what to expect in practice because I've never done anything at this high of a voltage with semiconductors.

Here are a few of the circuits that I have found so far.  I have seen a few Villard cascade circuits with resistors stuffed in them to change the loading characteristics and, I'm assuming to drain the caps for safety, but I can't seem to find any sort of equation that could explain things further.  Regarding the BJT circuit, it is pretty self explanatory, but I'm just not sure what to look out for or what to avoid when the voltages are that high.  The MOSFET circuit that I posted looks like a real bitch to implement.  Does anybody have suggestions or ideas before I start welding leads together on my protoboard?  What common failure modes should I be aware of with the BJT circuti?  Perhaps someone could post a better circuit than the BJT?

-Dave