SGNerf SMG mod for the Nerf N-Strike Stampede and 'MarcWF' on Deviant ART has taken it one step further; it just looks absolutely tough with the foldable front grip. You know what would really look awesome on it too? A pinpoint sight:D
It's also found on Etsy.com under 'Apex Weapon Systems' and I quite liked their other work too- they do do some pretty nice looking modded Nerf guns with performance and aesthetic alterations. Check out some of their other stuff, including the mad Dart Tag Quick 16 conversion to accommodate clips:D
I had my credit card out and was actually ready to buy this SMG but alas they don't ship to Australia...
NERF Stampede 12.6v SMG 'The Hammer' by ~MarcWF
Apex Weapon Systems via Etsy.com