Hi, SoapyAngel,
Have you tried any of BB's oxides (under "Pigments")? Unless I am mistaken (and someone please correct me if I am wrong!), oxides are non-bleeding. I know they can be tricky to use in M&P soap, but the pigment page has some instructions on how to use them. I like the idea of mixing the oxide with a bit of rubbing alcohol first to get the clumps out (or I suppose you could mix the oxide in with your fragrance oil if you don't want to add extra alcohol).
I have a list from BB's old website that lists non-bleeding colorants (and it looks like they're working on a similar page that's coming soon for the new website:
http://www.brambleberry.com/Webpage.aspx?WebpageId=34) and it lists the following liquid colors as non-bleeding: pink, blue, yellow, white, red, and violet. The black, brown, and green are supposed to be non-bleeding, too. Don't know about the deep purple, although the description doesn't say anything about bleeding. Be careful of the liquid orange -- it is FD&C based, so it will bleed.
Most micas are non-bleeding, like Soapbuddy and Bramble Momma said. I poked around the mica page and saw only a few that are described as being bleeding colors: the blue mica (cellini lip safe), coral mica, and shamrock green mica are bleeding colors, according to BB's descriptions.
Good luck at your craft fairs this season!