Aluminium Open Frame for Scrypt Mining RIG

This a design I made to build a custom frame made of 10x10mm aluminium hollow square bars (6x 1m needed). Corner slots are provided for first simple build of the frame. Then I provided hardened corners for making this build rock-solid (while keeping it light).

The "vitamins" for this setup are :
6x 1m 10x10mm (1mm thick square hollowed) bars,
106x 10mm M3 nuts (for frame build),
4x stantard nuts for fans,
8x 8mm M3 nuts for power supply support,
2x 10mm M3 nuts for back CG support bar,
4x 20mm M3 nuts (with 4 bolts) for back CG support bar,
hot glue,

1x seasonic 1250W 80+ Gold power supply,
4x Gigabyte R9 280x (should fit other models),
1x ASRock 970 Extreme4 motherboard,
1x AMD Sempron 145 CPU,
1x Kingston HyperX 4Gb DDR3 1600 MHz RAM,
1x Sandisk SSD 64Gb,
1x 200mm NXZT fan,
1x 120mm Noctua fan,
3x 16x-16x PCI-E risers,
1x 1x-16x powered PCI-E riser.

I can acheive 2900 KH/s with this setup at 82°C for the hotter card (others 74°C, 73°C, 78°