customization - Override database config for WordPress multiblog in WordPress

Well if you want to do this right, you would have one database for development, one for staging and then the live database. It's just that Wordpress ist designed to live with such commons in software engineering.

The component I still see publicly missing is a complete migration script that is able to convert all wordpress settings and data in the database from one domain to another as the domain names are "hardcoded" into posts and buried in multiple (often serialized) option values.

As long as you're concerned about the few options you listed only, you can hook into pre_option_... filters and change those based on your setup. You could write a define into your config file and change the values accordingly. This might work with multisite setups as well as you're filtering the actual values from the database.

Is this a direction?