Man it's tough. I've really struggled with this over the last couple of years. You'd be amazed at how many singers loose any original sounding qualities to their voice once you get them in front of a mic with music outside their "genre comfort zone". Plus they always seem to be the hardest to work with when it comes to directive and steering a project along. Maybe ego-clash or something, dunno.
Actually church choirs can be a decent place to find a vocalist as well.
yeah I've released a few tracks on the label that clipped samples and have gone completely unnoticed. actually have one coming out in a couple of months that has a very blatant sample. I'd agree with Meds, if it does blow up any controversy would only fuel sales

. Plus you can always pay a fraction of the copyright dues and buy download licensing if it does start to take off. I think the minimum is a license for 2500 downloaded copies and it goes up from there.
Are you looking for male or a female vocalist and what genre?