well looked like it should have worked but didn't.
VIRTUAL HOST /etc/sysconfig/network-scripts/ifcfg-br0
DEVICE=br0
TYPE=Bridge
BOOTPROTO=dhcp
ONBOOT=yes
DELAY=0
NM_CONTROLLED=no
IPV6INIT=yes
IPV6ADDR="2001:470:1f11:115d::1/64"
IPV6_DefaultGW="2001:470:1f10:115d::2/64"
VIRTUAL HOST /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE="eth0"
NM_CONTROLLED="no"
ONBOOT=yes
HWADDR=00:1D:60:9C:B8:1D
TYPE=Ethernet
NAME="System eth0"
UUID=5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03
BRIDGE=br0
VIRTUAL HOST /etc/sysconfig/network-scripts/ifcfg-he-ipv6
DEVICE=he-ipv6
BOOTPROTO=none
ONBOOT=yes
IPV6INIT=yes
IPV6_TUNNELNAME=he-ipv6
IPV6_AUTOTUNNEL=yes
PHYSDEV=eth0
IPV6TUNNELIPV4="209.51.181.2"
IPV6TUNNELIPV4LOCAL="192.168.2.201"
IPV6ADDR="2001:470:1f10:115d::2/64"
TYPE=sit
Now on the host ping6 ipv6.he.net works fine
GUEST /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=dhcp
TYPE=Ethernet
DEFROUTE=yes
IPV4_FAILURE_FATAL=yes
IPV6INIT=yes
IPV6_AUTOCONF=no
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
NAME="System eth0"
UUID=5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03
IPV6_DEFAULTGW=2001:470:1f11:115d::1 ## note 2001:470:1f10:115d::2 and 2001:470:1f10:115d::1 were also tried
IPV6ADDR=2001:470:1f11:115d::3/64
HWADDR=52:54:00:30:E5:9A
PEERDNS=yes
PEERROUTES=yes
Guest /etc/sysconfig/network
NETWORKING=yes
HOSTNAME=Fedora386Stable
NETWORKING_IPV6=yes
results varied from Network Unreachable to a ping that hung for minutes.
NOTE : HOST Centos 6.2 Guest Fedora 15 both x86_64