I think a poor man's fighter cube could work, so I took a shot at making rules. I tried to capture the idea of it being generally a poor, last ditch sort of idea, but if you can live with the limitations, it gets a lot of extra fighters into play.
The bay does not include any space for a pilot or technicians. Pilots must be allotted to passenger berths or cargo.
The bays are only the fighter's cradle, rocket boosters, and minimal micrometeorite protection for the fighter. When the fighter launches, the cradle is ejected and considered destroyed. Cradles weigh 50 tons when carried as cargo, but do not count against a ships weight when attached.
Fighters are loaded into the cradles following the rules for transferring cargo.
When mounted in a cradle, fighters may not be serviced in any way. No fuel, no ammo, no repairs.
The carrying ship can only use 2 thrust points/turn. Any more automatically ejects all fighter cradles as the brackets are not designed for the stresses.
Ejection bays are automatically ejected in atmosphere. Ejection bays mounted on a ship during a hyperspace jump are destroyed, along with any fighters and pilots contained.
Fighter pilots must EVA to their fighters and then re-pressurize the fighter. This process takes 1 hour, after which the pre-flight process begins. Pre-flight takes 50% longer as a result of not having technicians supporting. If the carrier spends thrust while the pilots are in EVA, the pilots must make immediate piloting rolls as if ejecting. Failure indicates pilot damage, while success merely indicates the pilot is tossed into space. On an unmodified result of 2, the pilot falls into the carrier's drive plume and incinerated, regardless of success.
Since the fighter cradle is ejected from the carrier, a ship to launch any number of fighters from these bays per round. However, the pilots must then detach the fighter from the cradle. Fighters attached to cradles may not spend thrust and follow the velocity and heading of the carrier at time of launch. Detaching the fighter requires a successful piloting roll, while failure indicated that the fighter did not detach. Fighters attempting to detach may not spend thrust, even if they make the piloting roll.
A dropship may carry 1 ejection bay per 1000 tons of mass. Stations, jumpships, and warships may carry 1 ejection bay per 10,000 tons. Ejection bays are 'mounted' on the side hit locations of the vessel (side/wing for dropships, fore/aft quarters for jumpers and warships, any location for stations). Maximum capacity per location is the maximum overall capacity divided by the number of valid mounting locations, rounded up. Ejection bays mounted on anything but a station must be mounted symmetrically.
Any weapon bays firing from the side or wing arcs of a carrier may not fire while ejection bays are still attached. Examples: An interdictor is carrying 6 fighters, 3 side/wing. While the ejection bays are mounted, the interdictor may not fire forward or rear wing weapons. A McKenna is carrying 60 fighters in ejection bays in the fore quarter locations. While the bays are attached, the fore quarter and broadside bays may not fire, though the aft quarter bays may fire as normal.
Damage inflicted to locations with attached ejectable bays do damage to the carrier as normal, but also strikes random fighters in 5 point groupings to the Nose location. If a fighter is struck, it is ejected though it is still considered attached to its cradle and must detach as normal. If a fighter is ejected in this manner while its pilot is in EVA, the pilot is killed.
