Take a look at Config::Merge (my module) which loads configuration from a directory tree of files in any of several formats (XML, YAML, ini, Perl, Config::General), merging them together into a single hash.

It has a second phase, that of merging in local overrides - you can override single hash keys, single elements in arrays, or whole sub-trees within the config. The default setup merges in a file called local.$file_type at the point where it finds it in the directory tree. However, in the examples, I show how you could customise this process to load this data based on (eg) host name, or whatever else tickles your fancy

hth

Clint