With 500t fighters capable of landing upon worlds and the ability to unload cargo without need of pesky cargo handling systems, we are missing only one thing. Ability to actually put cargo on a fighter.
What I propose is a 100t cargo hold for use in fighters. Cargo fighters could be used as an alternative to mass drivers, mineral haulers from the fringe systems or early colonization options that won't need to take up entire shipyard.
There would be no need to change anything else, as even if all fighter freighters are military ships, increasing maint. life of a fighter is fairly easy and they can be built to last for their whole expected lifetime.
Including early tech fighter "freighter" to show its fairly easy to make these work:
Gemenon Traveller class Freighter (P) 420 tons 3 Crew 41 BP TCS 8 TH 5 EM 0
572 km/s Armour 1-4 Shields 0-0 HTK 6 Sensors 0/0/0/0 DCR 0 PPV 0
Maint Life 37. 95 Years MSP 135 AFR 6% IFR 0. 1% 1YR 0 5YR 3 Max Repair 6 MSP
Cryogenic Berths 800
Commander Control Rating 1
Intended Deployment Time: 400 months Morale Check Required
Nuclear Pulse Engine EP4. 80 (1) Power 4. 8 Fuel Use 18. 29% Signature 4. 80 Explosion 4%
Fuel Capacity 50 000 Litres Range 117. 3 billion km (2373 days at full power)
This design is classed as a Fighter for production, combat and planetary interaction
Cryo berths used as replacement. If 100t cargo spaces followed trend of other cargo holds, they would cost 0. 5 durr and 0 crew, lowering the cost of this ship by 19BP and increasing maint life even further.