I plan to release the first Alpha version of Clay next month. I still have quite a bit of work to do to reach the milestone, but I hope to at least begin to get Clay noticed a little.
Clay's Installer uses apps in the form of packages, which represent releasable products based on Clay. ClayCMS is an example of an Installer package. Packages can also be utilities to supplement tasks within the Installer. One supplemental package I've worked on a little is a boot selector, which enables you to run different web sites from a single web root, using as many different packages as you want. When Clay loads up it is given a site name, which then triggers the boot for a specific package. Currently, if someone wanted to run multiple sites, we'd have to either use different PHP files for the entry point or different web roots. The boot selector acts as a go-between, providing the ability to use the Installer to choose which site boots to which package, and then hands over the boot to the desired package.
I've only been able to do minimal testing, as it has been locally and not using domains, but there doesn't seem to be any performance hit from using the selector. It does mean an additional class is loaded, but the class methods only determine which package is to be loaded and then the normal boot process begins.
I'm hoping the boot selector will encourage developers to create new projects based on Clay and utilize the Clay Installer.