mjamison..I understand you are in a terrible jam but most rescues are full because they pull from shelters that have low adoption rates. I would suggest you see if a friend or family member can take the cats on a temp. basis so that you won't feel so pressed to place them in a shelter.
After that, I would contact rescues again...not to ask them to take the cats...but to see whether they will provide you with a courtesy post on their website...ask whether they will allow you to bring the cats to an adoption event where they get to charge their normal adoption fee, but you act as the foster (meaning these cats don't take up space that could be filled with cats they pull from the shelter). Make sure you have your cats vet records and you should agree to allow the rescue group to charge their normal adoption fee and keep it.
Another thing you can do is post on Craigslist and on Petfinder:http://www.craigslist.org/about/cities.html
Select the city which is closest you to and then select Pets.
Petfinder has a classified section:http://www.petfinder.com/post/classifiedhop.html
There is also a really good PDF called "How to find homes for homeless pets". You can find it on my rehome page:http://www.natewood.net/Rehome.html