The fact that it's distro independent makes SRP perfect for tracking extra software that you've installed on any OS. For example, if you have a Red Hat Enterprise based system and want to compile and install the latest versions of Firefox and Thunderbird with some personal tweaks, using SRP (with an appropriate installation prefix) will make it possible to track the installation/upgrade of these packages without depending on or breaking the distro's packaging system.
In addition to being able to separate add-on software from distro software, you can then take your source packages and install them on any other operating system that can compile them. You can use this single packaging system to maintain packages for a heterogeneous group of machines (RHE, Solaris, HP-UX, FC5, Debian, etc).
SRP is written in Python, and has been implemented with cross-platform portability in mind, so using it on a Windows system isn't out of the question. This hasn't been tested at all on Windows, but would probably work. Might be especially handy for managing custom Cygwin installs...
The v2 sources can be browsed here or cloned from git://git.sourceruckus.org/srp2.git
The v3 sources can be browsed here or cloned from git://git.sourceruckus.org/srp3.git
SRP v3 will have a much cleaner code base, will remove a bunch of deprecated features, make the NOTES file format a bit more sane, and add a bunch of new features.