I was hoping that somebody might be able to shed some light on how to get this amazing metallic effect on fondant?

Is it some kind of edible silver foil? I have no idea - wouldn't even know where to start?

http://www.yummycupcakes.com.au/wedding-cakes-gallery

I am guessing that they could have sprayed the whole tier with edible metallic paint????

It's silver leaf, royal bakery posted this cake on her fb site and someone asked the creator the same question.

Wow, looked into the silver leaf and its flippin expensive!!!  I don't see me trying this technique any time soon!

You build the cost of the silver leaf into your pricing. That's if you have a business!

And gold leaf is more than twice as expensive :-)  I do quite a few of this style of cake, a style inspired by Faye Cahill. Google "Faye Cahill Images" and you'll see tonnes of silver and gold leaf cake designs.