> the holy grail of a P2P service which would allow me to initiate a connection ...

> the holy grail of a P2P service which would allow me to initiate a connection via CLI and get a simple URL to share with someone who could download the file from a web browser

    git clone https://github.com/jech/galene-file-transfer
    cd galene-file-transfer
    go build
    ./galene-file-transfer -to john https://galene.org:8443/group/public/somethingdifficulttoguess/ file.tar.gz

Now tell the receiver to connect to <https://galene.org:8443/group/public/somethingdifficulttogue...> and login as john with an empty password.