Thanks for the sub mate, and yeah it sucks when you have to figure out where the end product is. I'll add a Table of Contents as well, so that it's easier to navigate the build log. =) Will get to modding soon, need to do some final measurements which you can check out:
An mATX tray and and backplate will fit horizontally with ~3mm on both sides.
Power supply - You can fit an AX860i with 2cm to spare
Both the HDD and the SSD can actually be mounted with the power supply, since there is loads of space - http://i.imgur.com/hPIMFKw.jpg I can fit an ssd and an HDD next to the PSU (that's a shorter, old FSP350 but it will fit with the 860i).
Once you install a 200x200x25mm fan and a 36mm thick Phobya Xtreme 200 radiator you get 279mm space for your graphics card - The GTX680 which I plan to use is 25.4 (10'') in length so that leaves 224mm space to run whatever wires you need and so on.
Doing the back plate for the case will be a challenge but it can be done. I'll most likely use the current tray as support for the new one, but I will also add some blanking plates (with ventilation holes for the PSU/HDD/SSD).
The horizontal project is actually doable =D