Repeatable configuration package

Not exactly what you are asking for, but very close.

There is a concept of ‘dropin’ plugins that exists primarily to override or add to core functions

The dropins will always load.

So one ftp’s up wordpress including whatever plugin files you want that will create your default environment. These should be in the top level wp_content folder.

I have one called install.php which overwrites the pluggable function

wp_install_defaults

with my own set of defaults (starting pages, default widgets, categories, taxonomies etc etc. ) It could load starting options for other plugins as well and possibly activate them.

Then you click the famous 5 min install (the ‘script’ you mention). It installs wordpress and applies your custom options from the dropin plugin.

some brief information here:
http://hakre.wordpress.com/2010/05/01/must-use-and-drop-ins-plugins/
http://bucketpress.com/drop-ins-plugins