This is about True Type Fonts again.
Well, you actually stated that you don't want to let GS install the font permanently in the windows folder (this can already be achieved with an installer tool like InnoSetup), but maybe I can offer you another tiny, elegant and super-fast-to-implement solution

I tried to day writing a DLL which tries to add a truetype font temporarily with AddFontResource to the system font table
(click here for the related MSDN article). This works very well for other programs, but it doesn't work somehow with acknex. I don't know what you are doing in the engine

but maybe you could investigate that in your spare time to add such a feature into the engine which loads a fontfile (*.ttf) temporarily (even from
WRS!, that is important) so that we can use it in the game without installing it.
This is maybe the smallest and easiest solution to provide such a feature and many user will agree with my oppinion. Please do it ... we don't want to beg here.