Ok, so the only pedals I use as a bass player (and I have been doing this for a while) arehttp://www.guitarpcb.com
Stage 3 boost (you can find a kit for it on http://www.mammothelectronics.com/
) and the run off groove Ginger. The ginger is not a kit and not something a first time builder should attempt since you will need to source all of your parts and it is a pretty complex build (but an absolute monster for bass). The stage 3 on the other hand is very easy to build, comes in kit form (although not a BYOC), and sounds killer. Barry at guitarpcb has a great forum that will help you through your build.
Actually I believe Powerpop sent it to me...I put one of his fuzzies in mine.