I don't see a problem with the arrangement as long as the satellite and DVD player are not sitting directly on top of the 990 and 7700. The 7700 in particular needs some breathing room above it (preferably 2 to 3 inches). Putting the DVD directly above the 990 certainly makes sense since SACD will require six analog cables.

I don't think you'll have a problem with the power cord. The pre-amp cables will need to cross the 990's power cord but will miss the 7700's power connection (although the power cord from the 7700 may need to run toward the 990 and thus be parallel to the pre-amp cables to reach the power conditioner). Where the interconnects are briefly running perpendicular to the power cord, there should be no problem. If the interconnects are running parallel to a power cord over some distance, I'd try to maintain a few inches clear between the two. Balanced cables should reject noise picked up in transit from the 990 to the 7700, so you've got some insurance there, but a couple inches of separation would be some good insurance.