Auto performance tuning?

I have to say I've been really impressed with the quality and diversity
of tools here to increase performance for PostgreSQL. But I keep seeing
a lot of the same basic things repeated again and again. Has anyone
looked into a "smart" or auto-adjusting resource manager for postgres?

Consider for instance you set it to aggressively use system resources,
then it would do things like notice that it needs more work mem after
profiling a few thousand queries and adds it for you, or that a specific
index or table should be moved to a different spindle and does it in the
background, or that query plans keep screwing up on a particular table
so it knows to up the amount of stastics it keeps on that table.

Is this a crazy idea or something someone's already working on?

Orion