I guess @Spheerys is looking just for the slim black rim of the slim cover. That part is quite fragile when disassembled and has to be handled extremely careful.
That part is not available on it’s own; just as part of the slim case.
I guess, there are not enough black rims breaking to justify producing this part extra. And as the price for this part would be lower than shipping and handling, selling this part would possibly not be that easy.
But as there are quite a few users, that have reported cracked back covers (there’s a thread to that regard), they could have spare rims.
It could be worth a try contacting those users by pm.
Here’s the actual thred: