V13 has been made.
This version includes 'muncipalities'. When a town grows so big that another town's center tile is close to the boundary of its inner town zone (where the trees appear on roads in default climates) that other town is considered a muncipality. A Muncipality's population would be added to the company's score (this isn't done yet, you only get the news message). Muncipalities would use signs to communicate their wants/needs. A town can only agglomerate the closest 3 other towns (performance reasons). For now 3 seems enough. If people are having trouble I might consider raising/lowering this limit, 2-8 seems reasonable.
The advantage to the player is that you need to deliver a lesser amount of goods if you manage to get muncipalities. The disadvantage is that a: your exclusive area is smaller, and b: they might hinder building.
To disable the muncipalities setting the multiplier to 0 does the trick.
The multiplier determines how much of a size differential is needed to agglomerate. Setting it to 1 means any two towns can agglomerate. Setting it to 2 means double size is required.
By the way, you can agglomerate another player's town
