So after lots of research/experimenting/stacking/blending I believe I've found THE bass overdrive/distortion.
Providence - Vandal
It was a risk/chance or rather a stroke of luck here, because there is very little info around the web on these.
I was told that these were made for professional artists rather than or general sale, and that's why there is so few of them around.. Although I'm not sure whether that's completely accurate.
The guy that designed these series for providence now designs pedals for Free The Tone. So I figure the new 'free the tone - bass blaster' must be similar to the Vandal.
Here's what free the tone say:
Bass Blaster BB-2:
The Bass Blaster, previously only available for professional musicians, has now been added to the Free The Tone Custom line-up. The Bass Blaster is an overdrive pedal designed for the bass. The voltage is increased internally to +/-15Vdc in order to easily be able to control the wide dynamic range of the bass guitar. It has excellent touch response that the bassists request, and the sound characteristics are not lost regardless of whether the bass is played with a pick or fingers. The pedal creates the fat overdrive sound that most bass are looking for. Treble and Bass tone controls are perfectly matched to the characteristics of the bass and provide a wide range of tonal adjustment.
Anyway, I'm super happy with the vandal, just thought I'd share that. It would be cool to hear from anyone who knows anything else about these?
Cheers BC
Stephen