Belated fort update: I did, in fact, build one more random structure to the fort, a windmill. Every good Gorkamorka fort needs a windmill for power, so now all the random gizmos I built into the workshop can be put to good use.
I built it to be modular like the rest of the fort, not because I plan on having multiple versions I could swap out, but for ease of storage (a tall, skinny tower with sticky-out bits is just asking to get broken) and because you can move it around. It doesn't exactly spin well, but I still thought it was cool.
I used a bunch of random gears for most of the worky bits, as well as some high-voltage bushings that I think were part of the Mek Workshop that didn't make the cut for that section of the fort.
Anyhow, I think this officially ends the construction phase of the fort. Painting is now well underway and I hope to get the whole thing finished soon. Like soon soon, not a year or two soon. Fingers crossed!