I'm sure this will get shot down as adding too much complexity but hear me out as this was done in Grunt and makes Gruntfiles that much more awesome and readable. It's like SASS/LESS for config.
Format: <%= parent.child %>
Inserts: The value(s) with some intelligence as to not break anything.
[database]
name = "buckeye"
server = "192.168.1.1"
ports = [ "8001", "8001", "8002" ]
connection_max = 5000
enabled = true
[database.qa]
name = "<%= database.name%> QA"
server = "<%= database.server %>"
ports = [ <%= database.ports %>, "80003", "80004" ]
connection_max = <%= database.connection_max %>
enabled = <%= database.enabled %>
[database.stage]
<%= database.qa %>
name = "<%= database.name%> Stage"
enabled = false
This does not seem more readable to me, and increases the difficulty of writing an implementation by a significant margin. You could always use your favorite templating language to do this already and generate the resulting file.