I'd go for a Matamp cab if you can - superb cabs, solid as a rock, and will be similar to Mesa/Bogner cabs in tone given the similar construction levels. Beefy cabs = beefy tone.
'Blackback' Celestions are vintage speakers, I believe they are G12H30s from the seventies. The closest new model is the G12H30 Heritage (55Hz bass cones like the originals) and they are great speakers, but they're expensive.
V30s are the speaker of choice for most Mesa users, so I'd go with them if I were you. They're not that expensive to change if you don't like them. The most important thing is to get the right cab first, and for that I'd go with the Matamp :)