About half way done with a gcrypt special remote. I can initremote it (the hard part to get working), and can send files to it. Can't yet get files back, or remove files, and only local repositories work so far, but this is enough to know it's going to be pretty nice!
Did find one issue in gcrypt that I may need to develop a patch for: https://github.com/blake2-ppc/git-remote-gcrypt/issues/3