As a test - try shutting the machine down and then instead of clearing the CMOs, try unplugging the power lead from the PSU and then replace it and power on - see if you get video.
Another worthwhile test would be to cross-test the issue with a different CPU just to see if it is related.
Have you connected the additional power lead to the motherboard for the PCI-E slots? It is a molex connector.
In the meantime I will speak to a friend of mine who has this board..