The SCC being a chip developed only by Konami and Yamaha for specific applications (MSX and arcade systems), I doubt that it is still available somewhere, although you never know (I was quite surprised to see not long ago that VDP 9938 and 9958 chips were still available).
I suppose that Sunrise had to find them somewhere in order to produce the Manbow 2 cartridge.
I have some of these K051649 chips.
The real Konami typenumber is 2212P003 if you look for this you will find enough.
I bought them for €8,00/piece (this includes s&h).
I have some left to sell.
The real Konami typenumber is 2212P003 if you look for this you will find enough
Actually, he's right ... I made a Google search with that part number and found some retailers.
Actually, I'm not sure it is a retailer ... I wonder if maybe they wait for a customer to order and then subcontract the batch of components to some obscure chinese electronic manufacturer, using the original blueprint :-?