I'm the opposite. Have two Z16 WS boards, and I'd like to have more PCI slots. Memory is not an issue for me, 128Gb in 8 slots is more then I really need.I prefer the D16 over the D8 because of the extra memory slots. No real need to run SLI anymore, for me anyway.
If anyone want to swap D8 to D16 - Let me know.