I've owned a lot of dirtboxes, so I'm just going to throw out a few I was able to get decent sounds out of that you might be interested in: Fulltone Bass Drive, Xotic BB Preamp, EBS Multidrive, HBE Hematoma Bass Overdrive/Preamp, Boss Bass Overdrive. If you want to go the tube route check out the EBS Valve Drive and the EHX English Muff'n.
I've posted a few sound samples for various distortion pedals, you can find those here if you want to check them out:
http://www.talkbass.com/forum/search...archid=5680957
And I think there's better options than the Flipster for you. While the Flipster can create some overdrive, it's main purpose is to sound like an Ampeg Flip Top, which I don't think is what you're going for.