I Had No There Were Any Q3SP Mods
At least, any that weren't cancelled in 2004.
I was just wondering recently if I might want to map for Quake 3 if there were a singleplayer mod. Unfortunately, I don't think this is the one just yet; the enemies simply don't seem like they could be used to create engaging encounters.
Make Some Suggestions
I would reach out to Eraser with details on what you need. If there is something holding you back, it could be stopping others as well.
Q3 Technical Achievement With Great Documentation