Turret variation?

I was browsing through different pics of larger ships when it occurred to me that despite SC not being your typical sci-fi game, its turrets are very, very typical of the genre. What I mean is, in sci-fi, turrets always seem to have two guns. Always. In fact, I can't think of a single small or big-screen sci-fi where turrets don't have less than two turrets.

I would love to see turrets that had only one gun (without intentionally gimping the turret). Perhaps there could be turrets made available that carried a single slot that was a size up? Or perhaps a turret slot could be used instead for an additional cooler (for prolonging time to overheat), additional ammo for ballistic weapons, or an auxiliary power unit that allows the turret to be used even if the rest of the ship was shutdown/offline.

I dunno, just some thoughts I figured could spice things up. Make Turrets Sexy Again.

EDIT: By "turret" I mean "a manned turret with (a) gun(s)".