No stringers to be found, as far as I know, apart from the Sunova "rail stringers"
I may be totally wrong though
Plenty of boards come with stringers. It's just another design aspect/argument that people love or hate...or love to hate
Some say it makes the board too stiff. I have boards with stringers, and boards with no stringers. In my experience, shape dictates 99% of how these big boards feel, as they're large enough that I just don't notice the flex like you do with 2" thick shortboard. 4" of foam makes a board pretty stiff, and it's not like the average person is using 8' of rail in a turn ;-) On cheap pop-out's without a stringer, and simple (cheap) layup, I can really feel the flex. So much so that I've buckled them. My BP boards all have hardwood stringers, and Infinity boards don't. But with the carbon-PVC layup, the stringerless boards feel just as stiff to me. Which is to say, zero flex, at least not the flex you know when you've been surfing PU shortboards your whole life. It just doesn't matter. That said, I'd be pretty leary of any board that didn't have some kind of stringer system, whether it was right down the middle, or on the rails, if it wasn't using a high-strength sandwich layup like carbon and PVC, etc.