I haven't seen anything like that, but even if there was an event like that, they might not have released a DVD/Blu-Ray of it. I checked the F/SN anime site just in case, but I didn't see any other DVD goods except vols 1-8 of the anime and something called Fate/stay night curtain raiser（初回限定生産） which, if I'm reading it correctly, is just a DVD recording of the promotional events?
