Here is a look at NECA's Half Life Gravity Gun prototype model in progress (not final product). It will be released in Spring 2013.
The Zero Point Energy Field Manipulator (ZPEFM), most commonly known as the Gravity Gun, is a tractor beam-type weapon that was originally designed for handling hazardous materials, but, as Alyx stated, was primarily used for heavy lifting. At its core is a substance that appears to be a Xen crystal. Introduced to the player by Alyx Vance shortly after arrival at Black Mesa East, the Gravity Gun soon becomes an invaluable tool in Gordon Freeman‘s arsenal and is considered one of his trademark weapons.
The Gravity Gun will be limited, but not as limited as the Portal replicas were
It will be on display at NY Toy Fair this February