Telenet IPv6 and Status (september 2017, begin 2014)
Requirements (official)
Since 2013 the website of telenet announce IPv6.
One major (only?) information source seems to be the "Klantenservice". Searching for IPv6 gives
some information.
You need a "Telenet Wireless Modem 3.0".
In 2017:

Select "welke instellingen voor IPV6" will explain you need Telenet Wireless
Modem 3.0:

In 2014:

To verify your modem type access "mijn Telenet" in the right frame select "mijn modem".
For me this shows:

Rumor:
This White modem is the only Telenet modem supporting DHCPv6 with Prefix Delegation (RFC
3633, RFC 6603, RFC 7550).
DCHP Prefix Delegation is an easy way to obtain IPv6 addresses for your home subnets.
In 2014 it did show:

Status March 2014
In the week of 2 - 8 march 2014. A number of users of cs.kuleuven.be started ssh connections to
e.g. ssh[12].cs.kuleuven.be with IPv6 addresses of the Telenet range.
This indicates Telenet has started IPv6 on at least some of the home users installation.
Tests 20140314
A quick surveys of cs.kuleuven.be users confirms you need a modem with wireless
interface. Although two telenet customers (Heverlee, naamsesteenweg and Bierbeek)
have a modem with wireless access but no IPv6?