For those who purchased the Special Edition (Black Chrome) Leica 50mm Summilux ASPH and can’t find a suitable filter for it, perhaps there is hope (taken from the B&H website):
I don’t know if this filter will allow the lens hood or lens cap to attach properly (we’ll see).
—Peter.
Prosophos 
No cigar, I’m afraid.
I have been in correspondence with Leica since July on this issue, including asking this specific question. Here was their response at the end of November 2015:
“the new filters have the old style look, not the requested smaller fitting. As far as I know Product-Management have some new filters with them for examination. But I don’t know the results yet. As soon as I’ll receive closer details I’ll let you know. Sorry for not being able to help you now. Enjoy your day”
Oh that’s too bad.
He at least directed you to enjoy your day, though, so… that’s something.
Peter, if you don’t use the hood on the new limited edition Black Chrome 50 Summilux so that you can attach a filter, is there a lens cap that fits the lens. Because if the hood will not go over the filter and you want to use the filter, it looks like you then don’t have a hood or lens cap that you can put on your camera. From the picture you posted, it appears that you are using this lens with your M3. If so, how are you dealing with this issue? Thanks.