Have you tried "Soft Paws?" (I think they are also called "Soft Claws," but maybe it is a different company.) They are plastic-like blunt caps that you glue on over the claws. I use them on my kitty and while he may try to use my furniture as a scratching post, he cannot damage anything! He does not mind having them applied, he normally sleeps through it purring the whole time, but not all cats are ok with it. Most groomers will apply them for you if you have a cat that cannot handle it. If your cat is well mannored about having his/her nails trimmed then you shold have no problem with applying them yourself.
You can order them from the company's website (google it), or you can get them very cheap on ebay. :bounce: