The only short ranged system in KSA service I can turn up on a search is Skyguard 35mm.
ETA: Putin laughingly said maybe the KSA needs S400, but what they could probably really use is Pantsir.
For point defence I'd go with the German Mantis revolver cannon system paired with high powered laser system. Rheinmettal could provide both. Sensors and weapons would need to be elevated on flak towers for the best possible coverage.