Custom Photoshop scripting paths?

I've been researching how Adobe has or has not instituted custom scripting/preset/brush paths inside Photoshop CS5, so that we can keep all of our custom scripts/presets/brushes in a central repo, without having to symlink into the install path of Photoshop.

All the disucssions I have found online seem to date back to 2005 or earlier with no real discussion after that, which leads me to believe that there is a now a solution and I just haven't read the proper documentation to find it.

So .. how are you keeping your Photoshop application assets centralized?  Or is this just another one of those quirks where every other software developer manages to do it properly, but not Adobe?

Cheers,