Is there a simple installer file for PHP software?

If there is nothing like this, I'll probably write and release it for our software, but it could work for any software.

The background to this is that PHP powers 80% of web sites, and there is a huge number of commodity hosting solutions out there.

Basically, this would be a single PHP file that people would download and install on their favorite commodity host. Upon launch, it would

1. Look at some hardcoded index of https URLs

2. Download a zip file and check the signed hash

3. If the signatures check out (There would be a minimum # of signatures required) then unzip it

4. Change the file permissions and run installer

It would have a Web interface and a CLI interface.

I just haven't seen anything that's a single PHP file download. It seems like the easiest distribution model for commodity hosts which regular joes use.