can't you add screenshots here instead?
Looks like a model of Silverstone SG02, dimensions slightly different?
Unsure what your model has that is so different? other than 1 other slot. I have the SG02 and fit a wireless card and dual slot GPU with no issues.
SFX PSU 63x125x100mm
likely to foul the cpu/heatsink
Yes, but 2 slots are taken up by a duel width GPU on your board, a 5th slot lets you put a DW GPU in the last slot of the board & 3 slots are left...
This better? http://i.imgur.com/gsCAO0e.png
you'd want at least the height of the io shield above the io shield where the bottom of the psu should be , but how high would the case be then?
So you've designed front and back. what about the internals ie hdd's?