Fanatical VPS now supports IPv6 across all nodes & VPS plans. All new orders will be auto-provisioned with one IPv4 and one IPv6, if you currently have a VPS and wish to be assigned an IPv6 just send in a support ticket.

Unfortunately there are a few limitations with the SolusVM/OpenVZ/IPv6 combination, as described here:

venet devices are not fully IPv6 compliant, but still works if you statically assign IPv6
addresses. They do not properly support MAC addresses and consequently link local addresses and 
can not play nice with neighbor discovery or router advertisements, router discovery, or auto-
conf. They also require additional modifications to the layer 3 forwarding behaviour of the host 
via sysctl.

This means that you can't bind programs to listen on all IPv6 addresses, only your specific one, as described in the second half of this page.