Give us the Schrage Muzik option on the Bf110G. It will add weight and such, and we have no gunsight set up for it, but why not add it?
Set it up like a gunpod, only it fires upwards instead of forwards. The pilot would have to select the secondary weapon of "SMuZ" instead of "CAN" and fire only the secondary gun to get it working.
This would pave the way for a couple of Japanese twins as well, and for a few notable German night fighters. Sure in real life they were used at much closer ranges than in AH, but in real life bombers didn't fly as fast as most late ware fighters, and they didn't have lethal guns out to 1.5k, so why should the fighters that HUNT the bombers be so strictly limited?
It would burden any plane it's an option for (weight and some drag for the gun barrels), and would be a challenge to aim (no gunsight and limited ammo for each gun -- 3 drums of 60/90 rounds per gun for 2 guns, I believe), and would be all but useless against anything but bombers. Not to mention sitting fairly still underneath a set of bombers is a good way to get pilot killed by the ball turret!
Hopefully we'll see them on Ju88Gs and He219s and Ki46s, and any number of bomber killers. For the meantime I'd fly the 110G a lot more for bomber interception if it had this option.