Create a shortcut and add "+set fs_homepath D:\some_other_place"
I can't remember exactly how to enter it in Windows, but the command should work.
Cheers for that, I used a variation that still allows different users to have their files in different
dirs, my command line is :-
G:\games\OpenArena\openarena.exe +set fs_homepath G:\GameSettings\OpenAreana\%USERNAME%
Cheers,
Phill.