KTM SuperDuke, 2012 Aprilia Tuono, or maybe a Ducati Hypermotard 1100/796 or an Aprilia Dorsoduro 1200... There are all fairly similar to the S3. Some are a bit more motard-ish, but still in the vein of a liter sized naked. Are you looking for something to ride differently than the S3? or is it a matter of so may cool bikes it's hard to only have 1, because I totally get that.