Please allow me to preface my remarks that I am NOT a shill for the online community I am about to introduce you to. The community in question is a forum, similar to this, for professionals and amateurs that are into working dogs. There are many police K9 officers on this forum as well as dog-sport enthusiasts and personal protection dog trainers and owners. Some of them advertise on the site but, mostly, it's just for people to talk about working dogs and some non-dog topics although politics and religion are forbidden as well as anything sleazy, provocative, etc. Additionally, if you visit the site, you'll find that 99% of the members (or so it seems) are VERY pro-gun.
Anyway, this is probably the best working dog forum on the internet. There are breeders and trainers of some very serious dogs. There are also a lot of good people there. If you are interested in learning more about working dogs I encourage you to check it out.
Working Dog Forum -- Discussion of Working Dogs, Training & Breeding