You can have something like this in your .bashrc:

    multitail() {
        com="tail -f "

        for arg; do
            IFS=':' read -a array <<< "$arg"
            host="${array[0]}"
            file="${array[1]}"

            com="$com <(ssh -t $host 'tail -f $file')"
        done

        eval ${com}
    }

This will take the host:file syntax of remtail and turn it into Plugawy's example. I haven't tested it, but if you echo "$com" it'll spit out Plugawy's code.