It's pretty tricky due to the space requirements on a mITX board.
However the New ASRock X99E-ITX/ac will support 2x16GB DDR4 ram.
It's the only one I know of...
Although I think this is one of the only 2 stick DDR 4 kits:
Crucial Technology 32GB Kit (16GBx2) DDR4 2133 MT/s (PC4-2133) CL15 DR x4 ECC Registered DIMM 288pin - CT2K16G4RFD4213
The first questions that spring to mind are why you would genuinely need 32GB for a home system and why you need to limit yourself by choosing ITX?
16GB sticks are extortionately expensive right now
I have just been through this myself. There's the Asrock X99E-ITX motherboard mentioned above, and the Supermicro X10SDV-F which is based around an embedded Xeon D-1540 and will take up to 128 GB RAM.
You could build with an X99 Micro ATX form factor and not have to spend a fortune paying for 16GB DIMMS, a specialist board and a Xeon.
he has a problem justifying the expenditure to his wife
ASrock do a itx socket 2011 board that has quad channel memory thanks to using DDR4 Udimms, I think its for Xeons only, but they have managed to get it all on a small area.
http://www.asrockrack.com/general/pr...Specifications
Gigabyte X99M-Gaming 5
The case will depend on the graphics that you want but the Aerocool QS-102 is a cracking case if size is a major consideration. Obviously this doesn't support a full sized graphics card