I wrote a shell script that creates a new WordPress install in MAMP (directory, database, and security keys) based on your input into the prompts and sends you to wp-admin/install.php upon completion. I use it for every project and put it up on GitHub for others to use or fork.
Up 1
Another option to check out that sets up your local environment: https://github.com/AaronHolbrook/wpbuildr
Oh dang, that’s rad! I might have to integrate some of that.