Cremona Auditor on dedicated stand or Concerto Domus.
Not even Guarneri Memento... Why? Its stand it simply too tall for your room. My friend tried to put Memento's in room little bit bigger then yours(5m x 3.85m) with not so good resluts. You need to seat at least 2.5m from Memento's to get decent sound.
And forget about Amati Anniversario, Elipsa or Cremona. They are all way too big for your room.
You currently own Gamut L3? Good small speaker IMO.
Do you want one of the best small speakers? Then go ahead and try to audition Krell LAT-2000 or Wilson Duette.
Both(specially Krell LAT-2000!) are way better in all respects then Memento's IMHO. And I own Anniversario's BTW so, I am not biased against Sonus Faber.