Where's the sub hiding?
1) Running registered ECC which was dirt cheap from eBay 2) Yep 4*16GB. Reviews on Aliexpress will probably be your best bet to determine the max...
I bought this one. There are ATX versions as well. They're socket 2011 X79 supporting boards with 4 ECC RAM slots supporting quad channel, 2 m2...
Seems like the best place to post this. Took the plunge and ordered one of the Aliexpress X79 Chinaboards (the mATX one with two m2 PCIe slots)...