Currently Hawkular-Services and agent run with -Djava.net.preferIPv4Stack=true to force IPv4 networking. WildFly and EAP have support for IPv6 and can run without that flag. There are users out there that only use IPv6 inside their (internal) networks.
A quick smoke test shows that this is doable with H-Services .

Also Cassandra must be modified to accept IPv6 connections. See http://docs.datastax.com/en/cassandra/3.0/cassandra/configuration/configCassandra_yaml.html#configCassandra_yaml__listen_interface_prefer_ipv6

etc/cassandra-env.sh needs to have this line commented out:

# JVM_OPTS="$JVM_OPTS -Djava.net.preferIPv4Stack=true"

cassandra.yml:

listen_address: ::1
listen_interface_prefer_ipv6: true
rpc_address: ::1

Hawkular-services:

export CASSANDRA_NODES=::1
bin/standalone.sh -b ::1 -Dhawkular.backend=cassandra -Dhawkular.rest.user=jdoe -Dhawkular.rest.password=password -Djboss.bind.address=::1

standalone.conf: remove -Djava.net.preferIPv4Stack=true

standalone.xml:

  <outbound-socket-binding name="hawkular">
            <remote-destination host="::1" port="8080"/>
        </outbound-socket-binding>

After this, h-services runs on IPv6, localhost ( ::1 )

HawkFx can talk to it at http://[::1]:8080/

MiQ currently can authenticate against it on the IPv6 address and requests the initial list of feeds, and syncs inventory after some time.