We have a few places like this, one of them is SVN. There are currently about 122GB of files in the forums. I actually wanted most maps to be in the community maps mod. The problem with the forums is things get messy pretty fast.
The problem it tries to address is that wall towers are always more then 50% of the cost of walling. Can go much higher when you build smaller wall segments.
In compensation they get the shared "Sturdy Foundations" tech with stone towers and the tech is also more effective (give +50% more hp) so basically you can pay for having them at almostĀ same health as before.