This is pictures of the Sort Sunderland displayed at Royal Air Force Museum, Hendon, UK. If you want to learn more about the Short Sunderland read at Wikipedia.
Well as for a plastic model of the Sunderland you're out of luck. However there are a few vacuum form kits with resin and etched metal parts. One from Sinifer, one from Alpha Flight and two from Sanger. This monster would have a wingspan of 72 cm in this scale.