actually, i find it the other way around, the metallics are harder to find than the black and white.It's not confirmed if it's a permanent collection or not. You can try contacting a Chanel Boutique to find you one.. Even though it's quite hard to find the Cabas in Black / White right now. But yes, some other colors are coming out this fall.
Chanel SAs in London are mostly bad (not all but mostly).Chanel SA's in london are not that nice in london unfortunately!!
Called today and they said they are not doing it this fall