So, I have taken a few steps back to move a few more forward.
I've actually been using the Cube in the form you saw above for a couple of weeks or so and quite happy with it, but still knowing I need to finish it off.
In the meantime though I was thinking that perhaps there was a little more room in there to do something with. And that maybe I should look at the graphics side to match that a little more evenly to the power of the CPU.
Inspired by another build that put a Sapphire 7750 low profile into the Cube (albeit an aircooled Cube) I thought that it would be a nice thing to do the same thing in my build, but in keeping with the cooling scheme to watercool it.
Here is the virgin card:
and here it is being transformed:
I couldn't find a universal block that was low enough and had side outputs and was specifically for the 7750 so I took a gamble and modified an XSPC universal Rasa block. I basically ditched the mount bracket and removed the screws holding the heat transfer plate to the block and then used studding and nuts to secure the plate. This studding is on a 43mm x 43mm square which fits through the GPU holes....
The original rubber blocks from the aluminium air cooled heatsink are re-used to provide a cushioned contact for the GPU die and nuts are used on the reverse of the card to attach it.
To mount this card I made a new support piece that provides a route for a rigid PCI-e x 16 extender to come up through it and also to take a supplementary DC-DC converter board (photos to follow) and fix this all to the side supports of the Cube.
I lowered the motherboard another 7mm over where it was before - to give more space - and here is a trial fit using an old 775 ITX board:
Finally here is a first trial fit in the Cube base with single 120mm Noctua fan on the Alphacool radiator.
Obviously next things to do are now a bit more complicated....new panel, more water fittings, more things to figure out. Still, I am pretty sure one way or another it is all going to fit in there.