Yeah, it's possible using a voltage doubler circuit. I believe the DHA pedals use one to double the 12v input to 24v to feed the tubes. I've had a DHA VT2 and it sounded awesome, really fat and warm and could get a nice clean sound as well as balls-to-the-wall overdrive - take a look at the new VT1-EQ-Drive pedal. I REALLY want one, but since I want to build up a big crazy pedalboard, size and power supply issues are important to me so I'm looking at getting a Tech21 VT Bass instead. Also check out the soon to be released Aguilar Tone Hammer and EHX Bass Metaphor, they could be the next big thing.
Cream Pies are all out of stock now, but all the clips I've heard of them on bass sounded really farty to me anyway.