You don't have to look far to find a decent looking replica of the Plasma Cutter that Isaac Clarke uses in Dead Space. The character… specifically his attire… is somewhat popular at conventions, where cosplaying folks like to dress up as him. And they're all about accessories.
But nowhere has anyone seen one that not only looks as good as the "real" thing, but also behaves like it too:
According to Gizmodo, it took over 200 hours to construct, and it shows. The way the gun itself, as well as the green targeting lasers behave, is simply top-notch. Though what really sells Patrick Priebe's creation is the 1,500-milliwatt burning blue lasers that is able to actual deal damage.
Granted, it won't completely stop a Necromorphs, or your annoying next-door neighbor, dead in their tracks (unless the latter is made out of wood). Still, highly impressive, as well genuniely dangerous, nonetheless.