Have you contacted the rescues and asked? I would never have automatically disqualified an adopter simply because they had an intact male, providing there was a reason beyond "I want him left intact". It has been my experience that those people who have a valid reason for leaving a dog intact (such as competition requirements) are much more likely to take reproduction seriously and they tend not to make mistakes that lead to litters of puppies. I have adopted dogs to dog show folks who had intact dogs, and would do so again.
Don't assume you'll get turned down! Contact the rescues you're interested in and ask. If you have done that already and they did turn you down, your best bet might be to contact breeders and ask about retired and spayed breeding females. If you do go that route, you MUST spay the girl before she comes into your home. Don't put it off for even a day or two. An OOPS litter would not be in anyone's best interests.