I just tried to use the pci-e 1x for another 5830 in my 2x5830 rig using a 1x to 16x cable (which would make it into a 3x5830 rig).
I had partial luck...
The rig runs LinuxCoin. What happened was "aticonfig --lsa" listed all three devices, but "AMDOverdriveCtrl -h" only listed the ones plugged into 16x slots, even though it had a couple more entries in its table than usual.
When I tried to run phoenix miner on the DEVICE 2 that "aticonfig --lsa" listed, it tried to use the CPU...
If anyone could help me with my particular LinuxCoin issue, that'd be great!
It's not much, but I can offer 0.5 BTC for a complete solution.