I got my CZ from the son of an employee of BlackWing. I was calling around all over looking for one and the dude on the phone said his son had one he was selling. They are all over Armslist but tracking down a non Knapp silver receiver is hard to do now and the Knapp version is cheesy as can be IMO.
I personally like the Beretta 390 a lot more than my CZ just because of how it fit me. I also like the feel of the 391al more than the 390 but many people will debate about which one of the two is a better shotgun when it comes to reliability. I'm a huge CZ fan so it's hard for me to say I just didn't like the 912, but I didn't.
The CZ takes some breaking in and is PICKY about what you shoot out of it at first. I'd do some reading on shotgunworld (i think) and go into the Huglu forums and read up on the CZ 912.
If I didn't have a budget I would look at the Fabarm, I also know you like HK.
If you only plan on using this gun for clays only, seriously consider an OU as well. It probably won't be worth it for you starting out but when you get into clays you have more options with the OU. Different choke tubes and different ammo in each bore. CZ does have some decently priced entry level OU.
I was told to stay away from new Rem models, they just aren't what they used to be from what I was told.