As far as my experience shows, no. Photoshop 100% expects scripts to exist within specific folders contained within the application installation folder. This is a pain to deal with on Windows machines that have UAC enabled as it is not allowed for process to blindly write to c:\program files (and other locations) when UAC is on. The correct behavior is for the application to look for items such as scripts and plugins in folders under %appdata% or %localappdata%. It's amazing that Autodesk gets this right and Adobe couldn't care less.
What you can do is create a symbolic link in <photoshop folder>\plugins\scripts that is linked to a folder located elsewhere. Photoshop has no problem parsing the symlink and pulling the scripts in that way. That's what I used to get around the problem. While the installer tool for Volition's scripts still needs to have Admin privs to create the symlink, after it is done everything works fine from a user account with UAC enabled.