List of installed packages on gentoo with all use flags

I'm not completely against using package.env. If you understand and document it within your environment it can be a useful method to apply subtle changes with ebuild hooks whilst still tracking stable ebuilds.

I don't think it's an appropriate way to fix the revision of a -9999 ebuild though - according to the "principle of least astonishment". Nor does make.conf seem a very obvious place to fix package versions.

A cleaner approach would be to roll your own ebuild with Layman. If you name it django-1.2_pre12120 then it should be more obvious what it's doing and gives you an easy exit route once Django 1.2 is released and stabilised in Portage.

CentOS is very popular because of the upstream support by a lot of enterprise vendors and the rock-solid nature of the system. A move to any system like this is going to make you feel like you are trapped in a cage. You're clearly someone who enjoys tweaking (which I can agree with!). That being said, I think for a shared hosting system CentOS or Ubuntu Server is definitely a better approach as it simplifies management a lot.

In either case you'll need to invest some time (far less than the time required to learn Gentoo, IMHO) in learning it's tools and quirks. Once you get used to using apt or yum they're both quite tolerable for simple software installation.

In either case if your focus is PHP/Apache webhosting you could simply build a system using CentOS or Ubuntu and custom build your own Apache/PHP to meet your exact requirements. If I were you I'd spend some time seeing if the system packages offer anything like the configuration you're looking for (I know they both offer various MPM modules, for example).

In RedHat EL5 at least the mod_php default installation runs all PHP scripts as the www-data user, which would not allow access to all users' files (there may be something I'm missing here).