Have you seen these?
http://www.angelfish.net/yabbse/inde...threadid=14719
I just bought some and they came today so I haven't tried them yet. I like the idea that they will pull the finer stuff out of the water with the filter floss and that when you take them out to squeeze they won't leave a bunch of debris behind in the tank because of the hard enclosed case. At least...that's the idea.
I couldn't get in touch with anyone from Ultimate Sponges when I was looking for more, from their website. But I know you can buy some on AquaBid.