Hi Richard,
To make it sound like a Ducati you need a set of aftermarket slip-on cans at the least.
Personally I have carbon Sil Motor cans on my '99 750ss. They sound a treat.
You also need to consider the street "legality" of fitting this type of thing.
Budget is probably a consideration. From what I have learned Termignoni, Remus, Ducati Performance are all good options, but also at the upper end of the price scale.
I don't know for sure about 900ss cans fitting the new 1000ss but I would guess that they probably would as the bike is essentially the same shape.
For info regarding mapping etc try Neil at Cornerspeed -
http://www.cornerspeed.co.uk He fitted my cans for me.
Cheers
Phill