Just a small idea, if a Craft armament could modify the fuel capacity of a craft it could allow us to make some interesting trade offs in equipping craft for particular purposes such as scouting or in managing thouse far-far away UFO's. While were at it added radar radius would also be a possible effect.
Naturally this would require programming fuelMax and radarRange as excepted values on craft armaments and to modify the vehicle when attached and removed, I doubt the current code even uses dynamic values for these effects and just reads from the rule files so this would likely be a good bit of work perhaps most appropriate for the OpenXcomEx mod.