The Project Nix 
"Nix is a purely functional package manager. This means that it can ensure that an upgrade to a package can not break other than that you can always revert to the previous version, that multiple versions of a package can coexist in the same system, and much more. "
Nix Project at  http://nixos.org/O "


That would be fantastic, Mageia with a package manager so advanced. And the stable version 1.0 and warm from the oven now just came out: 5/11/2012!!!
For now, I think that only the package system uses NixOS Nix. What about shake the idea in Forum International to see the reaction Mageia staff?
The biggest problem of mixing packages and versions is breaking the distro and a manager that does not leave the system break down by more than make mixture of versions in parallel, unable to safely downgrade or even test other packages is almost a utopian dream ...
I was reading the site and found the link with packages for Debian, Ubuntu and Fedora. Yes, it has also RPM packages
You can view that at
http://hydra.nixos.org/view/nix/trunk/2644870

So surely the Mageia can have the package manager Nix.
Nix is a package manager for computer systems. Like RPM, apt and many other package managers, it is able to control the installation of packages, or named and versioned groups of files, such as software applications or their associated configuration data.[2] [3] [4]

Nix packages are configured using a lazy, pure-functional language especially designed for this purpose; shell scripts or any other external program (such as Make) may be used to build packages from source code. The purely functional nature of the system enables very precise dependency tracking; for example, a binary package has a dependency on the corresponding source package, on the compiler, and on other packages that the build requires. Cryptographic hashes determine the exact build and run-time dependencies of every package, and each source or binary package is represented by such a hash. As a result, binary package repositories are a transparent optimization of the basic operation of the package manager (similar to a "cache" of packages indexed by a cryptographic hash).

Dependencies are resolved by a system functionally equivalent to static linking, in that versions of software being depended on by a package are not removed until no package is dependent on them. This can lead to greater storage needs, but makes all upgrades safe (guaranteed not to break existing applications) and atomic. It also permits multiple versions of any package, including parametrized packages such as a program with and without a certain feature, to coexist with no interference.

Nix depends upon having its own directory structure for installing the packages. All packages are installed in sub-directories of the nix directory. In naming the folders, different versions of a package are identified by prepending the hash to the package name.

Nix can be used, with some caveats, as a package manager on top of an existing operating system, such as another GNU/Linux distribution. It may also be used to maintain any kind of file configurations, such as server setups, in addition to software packages in the strict sense.

Source at http://en.wikipedia.org/wiki/Nix_package_manager