Is the back plate swapable?

[EricCantona]

Does anyone know?

 

[VagrantWade]

Does anyone know?

It's unibody. So no.

 

[EricCantona]

Ah thanks

 

[tissotti]

Does anyone know?

Lumia 920 is carved out of one piece of polycarbonate, that also plays to that weight.
Nokia N9 Journey - YouTube

So no, backplate certainly isn't swapable.

 

[TenTwelve]

If you're adventurous and can get a hold of one you could swap your guts into a new shell. I may very well do this if I can get my hands on a gray body.

 

[tlo07]

It would probably be easier to just stick a gel case on it. I learned this lesson with my iPhone 4S. I ordered metallic purple housing for it and had it swapped out. It looks flippin' awesome but I can't tell you how many people have asked me "Where did you get that cool sticker for your phone?" or "Is that a case?". I could have saved myself $100 if I would have gotten a sticker or case instead! LOL!

 

[wp8nyc]

There are already tons of gel cases in all of the 920 colors all over eBay (not that I'd ever use one). That could be an option if you really wanted to change colors I suppose.