@Kathykins If you go into Manage Worlds you can change the default version of a Community Space to add a fabricator or anything else you like. I've completely remodeled the Community Space in Grims Quarry so that in its default setup it contains elements of the other three sub-assignments (community garden, marketplace, and maker space). This way I have access to things like planter boxes (indoor and outdoor), fabricators, vendors with market tables, recyclers, etc, without any voting requirements. It even has one of those food stalls with the yucky bug recipes that Sims seem to love (Sims are weird). You can find all sorts of pre-built versions of this type of Community Space in the Gallery if you're interested in something like this.
You can change all four sub-assignments while in Manage Worlds, but you are right you'd have to live in that neighborhood to be able to activate any of the other three sub-assignments through voting or cheats. In my builds it doesn't really matter which sub-assignment is active since I've made all four versions basically the same.
I agree, I would not want to put one on Sulani either-- it's too pretty and it doesn't have very many empty lots. I did put a community space in the Dachshund's Creek lot in Brindleton Bay. I gave it a bunch of holiday lanterns from the Holiday Celebration Pack and I change their colors depending on the season. I also gave it an outdoor fire for the winter months. It feels like an outdoor crafts fair. It has all of those same things in its default version (fabricator, planters, market tables + vendors, weird Sim townies munching on cricket popcorn, etc), plus it's a cat hang-out. :D
I created one more small community space in the empty 2nd floor of the Waterside Warble karaoke bar in San Myshuno. Since it's still a Karaoke Bar for its lot type it won't spawn vendors for market tables, but it works fine for things like fabricators, candle-making, juicers, etc. To me it felt like a nice addition to the Spice Market just outside the bar. The only downside of using this one is I have to listen to lots of awful singing coming from downstairs xD