I don't know how accurate you want, but for the price you can start with houndmistress on eBay. This replica of the costume was used in the Video for Terri Clark's song "Girls Lie Too". You can probably DL that to view it and see if it's what you want. I talked with houndmistress in July of '04 and she was selling an entire outfit for 425.00+ 7.00 shipping. That included the coat,vest,shirt,pants,sash,belt,wig,moustache and beard ,headwrap,beads,hat. You can then start adding some of SithCamaro's pieces for a more accurate look as you see fit.
I've seen Sithcamaro's Captain Jack in person many times, as well as several other Jacks -- Sithcamaro's is indeed the finest out there and he thoroughly researches every single piece as well as consulting many industry professionals who have worked on the film. I agree with Kris -- it doesn't get any better than his stuff... Highly recommended.