Mongrel2
mongrel2.org
mongrel2.org
What a horrible idea.
Mongrel2 has exposed it's internal configuration storage for programmatic manipulation in an easy and standard way. If you would prefer configuring it with a file, you could create your own configuration file format and loader. Good luck doing that with, say, apache.
Good luck putting your sqlite db under version control, templating it, modifying it easily from the commandline, etc.
The idea is just idiotic, especially considering how little configuration is needed in first place for something like a mongrel.
There's a reason why almost all services expose their configuration in a more or less human readable file.