Dear MargeCat and Family:
We must be sisters. I was born to serve cats, too.
You CAN get a "purebred" Maine Coon or Aby -- or both. Shelters are FULL of "purebred" cats. Many of them die for want of good homes. Cat "euthanasias" are at record numbers right now. I know this because I have friends who WORK in shelters and in "pulling" cats off the euth lists to rescue. Let your local shelter know who you are looking for in terms of "breed", or contact an organization such as http://www.bestfriends.org
, or Google (your breed)rescue organizations in (your locality) and you will probably be astounded at what you come up with. If not, you may want to join a Yahoo rescue group such as their Senior Cat Rescue Group at http://pets.group.yahoo.com/Senior-Cat-Rescue/
(they also have a non-age-specific cat rescue which I think is the same address without the "Senior") and you will probably find someone who can direct you to links of breed-specific rescues -- maybe even in your area.
There's absolutely nothing wrong with being compassionate. Quite the opposite, in fact!
And I'm so sorry to hear about your two guys; but it is NOT the gloom-and-doom picture often painted. Cats can still have quality of life and share lots of love with this and other health issues. So don't give up!