I'd be more than happy if there was an activity only light instead of a powered on light that doubles as an activity light.
Maybe I'm confused, but this is how the supermicro's work. All lights off with no activty, lights on for activity.
In my setup the FAIL light came on when there was a failed hard drive.
On my iStar cages, the green light is always on. When there is activity, that same green light turns orange. I think this is because each slot can be individually turned on/off so they provide a light to represent which slots are powered. This light turns on if there is a drive in the slot or not and depends on the slot being turned on.