Since bases are just objects themselves, it could be possible, but there are no plans to allow editing of individual objects in the first version. You will, however, be able to edit the proto traits for objects (eg, hitpoints). Only objects made after such an edit is done will gain those traits.

Trivia: The engine was going to support the placement of buildings in non-hook spots (the placement definitions still exist in the game data, but I haven't checked to see if the code to use them is still all there). This feature was going to be used for placing mine fields from I can remember.