I have looked and looked out here! It seems that nobody makes a simple clip to hold the camera in the rain. Is it just that nobody shoots in the rain? Absurd! Certainly somebody has had this issue. Any ideas? Thanks. Thomas PS I have a GearBox P&C camera cage to attach accessories.
There's this: http://www.digitalcameraworld.com/2012/09/20/diy-photography-hacks-stay-dry-with-a-hands-free-umbrella-holder-for-your-tripod/ and this:http://www.amazon.com/Haoge-Photographic-Umbrella-Bracket-Support/dp/B00WOF3IBC and: https://www.youtube.com/watch?v=g48ilaGbUhs probably not what you are looking for, and any wind and it defeats a tripod.
I've always used plastic-bag style rain covers: http://www.bhphotovideo.com/c/buy/Rain-Capes-Covers-Slickers/ci/3313/N/4075788778
Look at Bogen/Manfrotto. They make a huge variety of clamps and clips. You would need something that attaches to the tripod screw on the bottom of the camera and then holds an umbrella-size shaft. Might take a couple of pieces joined together. If you're using one of those "cages" to attach accessories to a DSLR when shooting video, then you may already be halfway there. It probably has a threaded hole that a clamp could screw into and then you just put the umbrella in the clamp.