E-3PO was the silver protocol droid with the foul mouth that lured C-3PO into trouble on Cloud City.  Now, it could be argued that this droid has already been made.  The Build-a-droid U-3PO was originally colored a bit too silvery and more closely resembled E-3PO, but it’s not a perfect match.  E-3PO’s midsection wiring had a silver/grey cast to it, rather than the black on most of the other protocol droids.  Similarly, Episode I’s TC-14 doesn’t work as a stand-in due it’s chrome shininess.  So, E-3PO is a bit of a lacuna.

E-3PO is a 3PO protocol droid.  It’s not terribly exciting but he’s got a couple of things going for him.  First is that he’s very easy.  A repaint of the BAD tooling or even one of the many C-3PO’s would suffice.  His patina probably doesn’t require a vac-metal finish.  He’s prominent enough that it’s surprising that he’s never even been attempted.  Perhaps Hasbro is afraid that parents would object to a figure of a character whose sole appearance in the film is cursing in an alien language.