The first round of Theme forces are coming out next week and it was confirmed that they aren't necessarily theme forces from the command books, but they are made up of themes that are well fleshed out in units.
To that end I'd say that we are probably looking towards getting either Storm Brigade, Grave Diggers or Sons of the Tempest.
They also mentioned, a while ago granted, that Sons of the Tempest was being trialled with CRA for Gun Mages. While I don't think this is enough of a change, I'll be curious to see if that stayed.
UPDATE FROM MOD: This thread started as speculation. The list is now out, discussion of it starts on the second page, around post 50. - Dave