I've been looking for a mod that gives the player an incentive to space out his factory a bit more -- currently I usually end up building multiple train-delivered factories very close to each other, resembling a giant factory blob (plus a couple mining outposts).

One idea I had to change this was to randomly generate some enhanced entities into the world that are unmineable, indestructible and cannot be built by the player. For example a high-range beacon with four module slots or a high-range substation or a row of fasterer assembly machines would provide a good incentive to build a factory next to them. You would probably want to make a mod-setting to enable/disable all of this if you end up doing it at all. I feel this idea fits with what your mod already does, hence I'm suggesting it here.

Of course you could add some more entities just for fun, for example a laser turret with higher range and damage stats or a small-range beacon that can use productivity modules.