I've got a rescue Lacy from Alabama, she's the absolute sweetest dog I've ever known. We weren't sure on her breed when we adopted her, but now that she's grown up a bit and we've done extensive research, we've come to the conclusion (with some Lacy expert help) that she's a Lacy. Check out this site:
http://www.americanbluelacyassociation.com/American-Blue-Lacy-Breed-Standard.html
Also, here's the Blue Lacy forum that I got a lot of info from. Not too many members, but the few there are very knowledgeable.
http://www.americanbluelacyassociation.com/forum/index.php
As far as breeders, I know of a couple, though I'm not going to pass judgement on them, as I haven't got a puppy from any of them.
My experience with them has been wonderful. I can only speak from experience with a single dog, however, as Lilly is the only Lacy I've ever owned. She is such a wonderful dog. She is friendly, loving, loyal, and VERY energetic. Remember, these are hunting dogs, bred to be fast, agile, and track for miles, so they need adequate exercise. Lilly on average needs an 1-2 hours of outdoor play/running a day. They are great indoor dogs if exercised enough. She gets along with all dogs, has never had an issue with human or dog. They do, however, have a fairly high prey drive and will bolt after just about anything that moves outside. A proper recall is an essential tool. She is fine with cats and small dogs, though.
They require minimal grooming, have very short hair, not a crazy amount of shedding, responsive to training, LOVE swimming, and are high energy.
My best suggestion would be to go to the Lacy forum and ask about the breed.
Personally, I love them. Though they're not for everybody. (no breed is, really)
Lilly: