For my current project I need a 12V Analog output. Today I did some first tests.
I used a voltage regulator which is rising the 5V of the Pi to 12V. The reason is, that I want to be able to power the whole thing with a standard power bank.
Getting a PWM signal
I used the SoftPWM FB from the GPIOMods project to get a PWM signal out of GPIO4.
To drive a voltage that is higher than 3.3V, I used a usual combination of an NPN and a PNP transistor. I just had not the correct resistors at hand, why lower volatages can't be correctly reached (you will notice in the video ;) )