Right now we only have this forum post which in turn links up to a HP webcast chat transcript as authoritative info about how long the cals will be sold to:
The Future of SBS 2011 CALs?:
Why OEMs get through 12/31/2016 and retail and VLSC only gets until 6/30/2016 is beyond me. Eric Ligman says that we should do VLSC and not OEM and yet in the small biz space Microsoft constantly reinforces how wrong of an idea that is.