Dear Chuck,
I have one somewhere but almost never use it because it's too easy to poke the filter with the lens, which goes straight through the spring clip. At least this may make you feel better if you can't find one...
I also have a Nikon screw-in gel holder but the rubber that holds the gel went horribly sticky and slimy. Then there's the Kodak porte-filtre, which holds gels in frames...
There are lots of options but few if any are 'magic bullets'.
Cheers,
Roger