I'm fairly sure that you can sit down with one of those Craigslist breeders (or whoever else) about how the purpose of neutering is to prevent unwanted puppies, and that you don't want to alter the dog's behavior or health by changing his hormonal state. Most vets will perform a vasectomy on a dog for the exact same cost as a neutering as it's a simple procedure. Ask the person if they will accept this method of sterilization as fulfilling the neuter requirement. If they're not a complete idiot, they will do so.
Oh, and obviously don't get two male dogs, especially two intact males; are you fucking insane?? Supposing you get an apartment/whatever big enough to comfortably house two large dogs, the best situation for you would be an intact male and a spayed female. The male will probably still attempt to hump at the female, but she won't take any of that nonsense and will keep him in line without any real risk of fighting. This will also make him a lot hornier and he'll want to fuck you even more than he already would.
But seriously, don't get two male dogs, especially if they're intact, and DOUBLE especially if you're going to fuck them. They will literally attempt to fight to the death over who gets the right to breed with you, and there isn't anything obedience training can do to stop it.