Steve, the more I think about it the more I'm thinking of replicating the relevant elements from the huge ships. Currently I'm looking at a main base card for the control tower and the deflector building (the central buildings) and at least a hull and shield value for the two landing pads. The lasers could simply use the existing 'Single Turbolaser' card that comes with some of the huge ships, though each one would have its own hull and shield value. Dropping the man main shields would knock out all other shields, but it would have a value comparable with a huge ship, so probably about 6. The turrets would have a value comparable with a small ship, with the landing pads perhaps slightly higher. The landing areas would have to turn their shields off to release or accept fighters.
Using the existing single turbolaser card would mean the the base would generate energy as per the huge ship rules so the lasers would have to be charged. That might make them less devastating. The main base could probably take at least two crew cards too.
Just some more thoughts while the primer dries.