My 2 cents (some will not agree):
What is your budget, and what kind of vehicle are you schlepping with?
Two 4x10s is a whole lotta heavy gear, and if you buy cheap 4x10s, they won't sound as good OR as loud as a more expensive 2x10 or 2x12.
I run two high-quality 2x10s and have never had any trouble filling any room with sound. True, I bought really, really good cabs - they were about $750 each - but lord they sound great AND I can put them in the back seat of a car. I am 100% confident that if someone side-by-sided them with a less expensive 4x10 or even two 4x10s, they'd prefer my rig.
That all said, if I wanted a BIG ROCK RIG, I'd look at a Berg 4x12 cab or two 2x12's. I see these for sale used now and again. Great cabs, reasonably light. You then have to get a good head with some real headroom to it.
So Shaun, what's your budget? And why are you married to the idea of the amp & cab coming from the same company? I've always had better luck mixing and matching.