I go along with Greggie on that one...I use real bucktail on my jigs because there's such a difference in the way it moves in the water...also a big diffeence in the frequency of hits on bucktail as opposed to nylon...can't bring myself to use the synthetic stuff...but if you're gonna use the nylon stuff & need a lot of it I'd start looking at a good fabric shop, there's some surprisingly good stuf to be found there...good prices as well
There's a line of bucktail jigs made in my local area that use synthetic FishHair instead of bucktail. It's the closest I've ever seen to the real thing, but kind of expensive at $4 for a 1 oz pack. Bass and blues like it.
I get the 4" stuff from Stamina, Jann's Netcraft has it, too, and I seem to recall seeing a 6" variety on the web recently, but I don't remember where.