I'm also interested on this question, could you please expand on your answer?
joan wrote:The Pi needs 5V unless you are powering it in an unconventional way.
I feed 5V into a breadboard. I use the breadboard power rail to power both the Pi (via the expansion header) and servos. There is no reason you can't do the same, electrically if not physically.
The problem as I think to see is that if you use a 5v psu, split into two and power from there the rpi and the servos, the servos will drop the voltage for the rpi shutting it down. But I'd have said that the servos can draw intensity, not voltage, so that you could solve that by using a 5v 10a psu for example. I'm wrong then (but why?).
My point is the same as the topic (I'd say), how to use one single power supply for both the rpi and 2 servos? From my electrical ignorance, it seems not logical that you have 220v in the wall and you still have to use 2 psu to power these 2 devices.